diff --git a/CLAUDE.md b/CLAUDE.md
index 9d82a14..76d822c 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -39,7 +39,7 @@ The detail lives in `docs/claude/`. Read the files that touch the area you are e
 | File | What it covers |
 | --- | --- |
 | [build-and-run.md](docs/claude/build-and-run.md) | Configuring and building, the desktop-entry target, the command-line options, and the two vendored dependencies (`deps/plotter`, `deps/udpsclient`) including what was changed upstream and why. |
-| [verification.md](docs/claude/verification.md) | How to run the headless self-check, the **two baselines every run is read against** (exactly three build warnings; no `Gtk-CRITICAL`), and the environment variable that schedules each probe. |
+| [verification.md](docs/claude/verification.md) | How to run the headless self-check, the **two baselines every run is read against** (exactly one build warning; no `Gtk-CRITICAL`), and the environment variable that schedules each probe. |
 | [probe-readings.md](docs/claude/probe-readings.md) | The per-line reference for the self-check's output: what every probe and dump line means, the value it must read, and the defect a wrong reading names. |
 
 ### How the application is put together
diff --git a/CMakeLists.txt b/CMakeLists.txt
index eb8c066..f3a9785 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -151,7 +151,7 @@ add_custom_command(
 # The generated source carries each file as one C string literal, and a `.ui` is big enough to pass the
 # 4095-character minimum the standard requires a compiler to support: `-Woverlength-strings` fires on
 # generated *data*, not on anything anyone wrote. Silenced for this one generated file (the icon bundle
-# is small enough per file never to need it), so the build stays at its three warnings. The manual is
+# is small enough per file never to need it), so the build stays at its one warning. The manual is
 # no longer compiled in, so the help bundle's own warning is gone with it.
 set_source_files_properties(${CMAKE_CURRENT_BINARY_DIR}/udpscope_ui_resources.c
                             PROPERTIES COMPILE_OPTIONS "-Wno-overlength-strings")
diff --git a/README.md b/README.md
index cea447c..ded6c36 100644
--- a/README.md
+++ b/README.md
@@ -123,11 +123,17 @@ click on a result fills the address, or **Use MAC** fills the MAC and leaves the
 saved: only the filled field is. A MAC with no subnet is looked up by a broadcast sent on every up interface: a
 single limited broadcast leaves through the default route only, and on 2026-11-02 it missed a real board on
 `net0` while the default route was `wlan0`. The form also groups the acquisition settings (scan rate, external clock,
-trigger, restart after an overrun, factory calibration, the digital poll rate), a range per analog input, and the
+trigger, restart after an overrun, factory calibration, the digital poll rate, the generator update rate), a range per analog input, and the
 direction and initial value of each digital line. The analog inputs are the plotted channels; each digital input
 and the counter is an extra channel only if you ask for it. Two side-stack tabs belong to it: **Analog out**
 (per DAC: a static level, or a sine, square, triangle or ramp from 0.1 to 10 Hz) and **Digital I/O** (a live LED per
 input bit, a switch per output bit, the counter with a reset); they are insensitive while no board is connected.
+The waveform generator writes the DACs at the **generator update rate** (`gen_rate`, 1 to 200 Hz, default 50), which
+is separate from the input poll rate (`poll_rate`, which only reads the digital inputs and the counter). Each update
+is a synchronous command to the board, so a board that answers slowly achieves less than was asked: the **Analog out**
+tab ends with an **Update rate** row that shows the rate the generator actually achieved (measured over about a
+second) next to the requested one, or `off` when no generator runs. The waveform frequency itself is still limited
+to 0.1 to 10 Hz.
 Acquisition is hardware-paced only (the scan rate or an external clock), the channels times the rate must stay at
 or below 250 kS/s, and the form refuses more. With the command-line options, a run that names no `aiN` key gets
 `ai0=BIP10V`; naming any `aiN` key drops that default, so `ai1=BIP5V` alone is channel 1 alone.
@@ -2909,7 +2915,7 @@ now — they are listed so they are not mistaken for anything else:
   unlocked, because configuring the host is what a first run is for. Each pane's heading also carries its **own switch**, the same control as the
   header bar's button — clicking either moves both — because a pane that is *disabled* while its
   feature is off is a pane whose controls you would otherwise have to leave to turn it back on. The
-  switcher's policy is `wide` and each page has a title. With the math
+  switcher's policy is `wide` and each page has a title and no icon (the switcher's own placeholder icon is hidden). With the math
   list folded into the signal list under a `MATH` divider whose `+` creates a channel — a derived channel already *is* a channel in
   the model, so the two lists were the same list drawn twice. A tab is one-of-*N*, so no
   toggle hides a pane any more: cursors-off **disables** its readout and leaves it in place, and
diff --git a/docs/claude/architecture.md b/docs/claude/architecture.md
index 9b21c8d..b295015 100644
--- a/docs/claude/architecture.md
+++ b/docs/claude/architecture.md
@@ -51,7 +51,7 @@ What feeds `Acquisition` is a `DataSource`, one of the registered *kinds*.
   never reaches the UI files.
 - The E-1608 source runs **everything inside `poll()`** on the producer thread: posted commands, the
   connect state machine (Down, Scanning, Halted), the scan read, the 500 ms status check (its not-running restart is skipped when a hardware trigger is configured), the digital
-  input/counter poll and the 20 ms waveform tick. There is no second thread. A connect attempt (discovery,
+  input/counter poll and the waveform tick (every `1 / gen_rate` s, 20 ms by default; one synchronous DAC write per running channel, so a slow board lowers the rate it achieves, which the Analog out panel reports). There is no second thread. A connect attempt (discovery,
   handshake, calibration read, scan start) can block `poll()` for as long as the command timeout allows each
   step; that delays only the command queue. Every exception is caught inside `poll()`: an escape would end
   the producer thread, and `drain_commands()` runs inside the same `try` for that reason.
diff --git a/docs/claude/build-and-run.md b/docs/claude/build-and-run.md
index 9cbff1a..4e78ed1 100644
--- a/docs/claude/build-and-run.md
+++ b/docs/claude/build-and-run.md
@@ -118,7 +118,7 @@ is exported when the option is absent, so GTK's own choice stands.
 `--source e1608` selects the MCC E-1608 Ethernet DAQ; its settings are `--source-opt` keys, all optional
 (`address` or `mac`+`subnet`, `port` 54211, `code` 0, `timeout_ms` 2000, `scan_rate` 1000 per channel,
 `ext_clock`, `trigger` `none|rising|falling|high|low`, `auto_restart` 1, `calibrate` 1, `poll_rate` 10,
-`mode` `se|diff`, `ai0`..`ai7` `BIP10V|BIP5V|BIP2V|BIP1V` (an absent key = off, **and any `aiN` key at all
+`gen_rate` 50 (Hz, 1 to 200: the waveform generator's DAC update rate), `mode` `se|diff`, `ai0`..`ai7` `BIP10V|BIP5V|BIP2V|BIP1V` (an absent key = off, **and any `aiN` key at all
 drops the default**: only a run with no `aiN` key gets `ai0=BIP10V`, so `ai1=BIP5V` alone is channel 1
 alone, and a value that is not a range name is a channel that is off), `dir0`..`dir7` `i|o`,
 `plot0`..`plot7`, `plot_counter`, `do_init`, `ao0_init`, `ao1_init`). Either `address` or `mac` is
diff --git a/docs/claude/invariants-gtk-and-chrome.md b/docs/claude/invariants-gtk-and-chrome.md
index 9d24b0d..c594499 100644
--- a/docs/claude/invariants-gtk-and-chrome.md
+++ b/docs/claude/invariants-gtk-and-chrome.md
@@ -252,7 +252,12 @@ Part of [CLAUDE.md](../../CLAUDE.md). These are rules that cost a defect to lear
   session file. An icon-only version existed (policy `narrow`, empty titles, the pills named in code by
   `name_side_tabs()`, because `narrow` still draws a label beside an icon); it was reversed because the
   glyphs were not understandable. A page added with an empty title is a blank pill, and
-  `switcher: … pills=N labels=N pages=N` reads it as `labels` below `pills`.
+  `switcher: … pills=N labels=N images=0 pages=N` reads it as `labels` below `pills`. **No icon at all**
+  is not what "no `icon-name`" gives you: `AdwViewSwitcherButton` always builds a `GtkImage` and falls
+  back to `image-missing` (the `[x]` placeholder, which also squeezed the title to "Meas..."), and no
+  property turns it off. `keep_tabs_icon_free()` (`src/ui_source.cpp`) hides every image in the switcher,
+  re-hides one that is shown again, and re-runs on the stack's `items-changed` (connected *after* the
+  switcher's own, so the new button exists) and on the switcher's `map`; `images=0` is the reading.
 - **An *overlaid* sidebar covers the plot, so a drag out of it has nowhere to land.** `collapsed` in an
   `AdwOverlaySplitView` means the sidebar sits *on* the plot rather than beside it: the pointer is over the
   list, never over a drop target, and a signal can be dragged but not dropped. `row_drag_sidebar()` hides
diff --git a/docs/claude/probe-readings.md b/docs/claude/probe-readings.md
index 8585e82..36faa0d 100644
--- a/docs/claude/probe-readings.md
+++ b/docs/claude/probe-readings.md
@@ -479,9 +479,15 @@ Two lines of the self-check output are assertions in disguise:
   substitutes a missing-image placeholder, the button still works, and every other line of the
   dump still passes. Changing an icon name is a one-line change in `build_toolbar()` and this
   is the only check that it names something that exists.
-- `switcher: policy=wide pills=4 labels=4 pages=4 size=308x34` (in the exit dump, beside `panels:`) — the
+- `switcher: policy=wide pills=4 labels=4 images=0 pages=4 size=308x34` (in the exit dump, beside `panels:`) — the
   sidebar tabs as the switcher actually draws them, and they are **words**: `labels` counts *mapped labels
-  with text*, so `pills=labels=pages` says every page has a visible title. `pages` is read from the stack
+  with text*, so `pills=labels=pages` says every page has a visible title. **`images` must be `0`**: it
+  counts *mapped* `GtkImage`s inside the switcher. `AdwViewSwitcherButton` builds an icon in every tab, and
+  a page with a title and no `icon-name` gets `image-missing` -- the `[x]` placeholder; the tabs hide it
+  (`keep_tabs_icon_free()`, which also covers pages `build_source_panels()` adds). A nonzero `images`
+  names a tab still drawing an icon or its placeholder (`images=pages` is the unfixed state), and
+  `pills`/`labels` never saw it. Read it on a source with extra pages (`--source probe` under
+  `UDPSCOPE_PROBE_SOURCE_KINDS`) as well as on UDPS. `pages` is read from the stack
   (2 for UDPS, 3 for the probe source, 4 for the E-1608 with its Analog out and Digital I/O tabs). A
   `labels` below `pills` is a page added with an empty title; `pills=0` means nothing is mapped, which
   makes the rest of the line meaningless rather than a pass. `policy=wide` is read rather than assumed.
@@ -1832,7 +1838,7 @@ kind, so a run without it never shows that kind. The `form` line appears once pe
 - `kinds=udps,e1608,flatudp,probe`: a missing kind means `register_builtin_sources()` was not called before `parse_args()`,
   or the env var gate is wrong.
 - `round_trip=0`: a form's `write` and `read` disagree about a key -- a renamed `SourceConfig` key, or an
-  absent key that was not defaulted. `valid=0` is a default configuration the form refuses. The e1608 form's sample sets address, port, scan_rate, mode, ai1, trigger, dir1 and plot0; a mismatch names one of those. The flatudp sample sets port, bind, multicast, iface, rate, endian and signals.
+  absent key that was not defaulted. `valid=0` is a default configuration the form refuses. The e1608 form's sample sets address, port, scan_rate, mode, ai1, trigger, dir1, plot0 and gen_rate; a mismatch names one of those. The flatudp sample sets port, bind, multicast, iface, rate, endian and signals.
 - `panel disconnected: sensitive=0 present=1`: **disable, don't hide.** `present=0` is a panel that was hidden
   or never added; `sensitive=1` is a panel that stays live with no source behind it.
 - `panel connected: sensitive=1`: anything else means `apply_source_panels` acted on the wrong widget (it must
@@ -1859,6 +1865,8 @@ The UDPS run has no `source-` page in `side_stack`, because the UDPS kind has no
 [e1608] scan socket closed by the board
 [e1608] reconnect: connects=2 connected=1 ok=1
 [e1608] resumed: frames_before=612 frames_after=662 ok=1
+[e1608] generator: requested=100.0 achieved=99.7 panel='100 Hz (requested 100 Hz)' ok=1
+[e1608] generator stopped: achieved=0.0 panel='off (requested 100 Hz)' ok=1
 [e1608] scan: found=1 ip=172.21.121.113 mac=00:80:2f:00:16:08 status='1 board found' fill_addr=1 fill_mac=1 rescan_replaced=1 ok=1
 ```
 
@@ -1895,6 +1903,17 @@ the one `[e1608] handshake with ...: Connection refused` line, `stream: ... sign
   drop (neither the scan read nor the status check raised it), `resumed: ok=0` is a reconnect that did not restart
   the scan (it also reads 0 when `connects` is still 1, since a frame count that grows on a link that never dropped
   proves nothing).
+- `generator: requested=100.0 achieved=99.7 ... ok=1`, `generator stopped: ... ok=1`
+  (`UDPSCOPE_PROBE_E1608_GEN=1500`, a run of its own with `gen_rate=100`): `requested` is `gen_rate`, `achieved`
+  the source's own measurement (generator ticks that wrote, per second of wall time, over a window of about 1 s),
+  `panel` the subtitle of the Analog out panel's "Update rate" row. `ok` needs `achieved` within 70% to 110% of
+  `requested` **and** the panel to quote the requested rate; the mock answers at once, so it reads within a
+  percent of `requested`. Far below is a `run_timers()` that re-arms with a constant (the 20 ms the setting
+  replaced reads 50) or a tick that runs late; `panel='off'` while `achieved` is non-zero is a panel that
+  did not refresh (it ticks only while its page is on screen) or one that reads the wrong readout. This line says
+  nothing about a real board, whose DAC writes are slower; there the same row is the measurement. The stopped
+  line must read `achieved=0.0` and a panel that starts with `off`; a non-zero value is a rate that
+  `update_gen_flags()` did not reset when the last generator stopped.
 - `scan: found=1 ... ok=1`: the form's **Scan network** row against the mock. `found` is the result rows after
   the first scan; `0` with the second line `did not answer` is an environment with no up, non-loopback
   broadcast interface that reaches the mock (or a refused broadcast), **not a pass**. `ip` is the listed address
diff --git a/docs/claude/verification.md b/docs/claude/verification.md
index e840516..92c7393 100644
--- a/docs/claude/verification.md
+++ b/docs/claude/verification.md
@@ -15,23 +15,21 @@ xvfb-run -a env UDPSCOPE_EXIT_AFTER_MS=8000 UDPSCOPE_ENABLE_ALL_MS=1000 \
 
 Two baselines every run is read against. The UDPS runs must be **unchanged by the source-plugin work**:
 a UDPS self-check, number-normalised (`sed 's/[0-9.]\+/N/g'`), diffs empty against one taken before it.
-A clean build emits **three** warnings and no more: two
-`-Wmissing-field-initializers` on `MathNode::source` and one `-Woverlength-strings` on the icons'
+A clean build emits **one** warning and no more: a `-Woverlength-strings` on the icons'
 generated GResource `.c`, whose blob is **9248** against C99's 4095-byte string-literal limit with
 the five action icons and the two app icons that remain (a note about a generated file, which GCC
-itself supports). The *fourth* was the help pages' generated `.c` (**516044** bytes); the manual is
-now a Mallard set installed for Yelp rather than a GResource compiled into the binary, so that
-bundle — and its warning — is gone, and the baseline moved from four to **three**. Re-measure by
-touching each `*.gresource.xml` under `src/` and rebuilding; a third `-Wmissing-field-initializers`
-or any other warning is a finding. (The fifth warning that used to appear here was an unused
-`output_built` in `math_probe()`; it was **deleted** as dead code — redundant with the
-`output_after_add` already printed on the same line — which dropped the baseline from five to
-four.) And an exit-dump run emits **no** `Gtk-CRITICAL` at all, nor any `Gtk-WARNING`: the dump's
+itself supports). History: the help pages' generated `.c` (**516044** bytes) went when the manual
+became a Mallard set installed for Yelp; an unused `output_built` in `math_probe()` was deleted as
+dead code; and the last two, `-Wmissing-field-initializers` on `MathNode::source` in `math_probe()`,
+went when the probe's `MathNode{MathOp::Gain, {}}` / `MathNode{MathOp::LowPass, {}}` named the
+field (a partial brace-initialiser on `MathNode` re-adds one: `source` has no default member
+initialiser). Re-measure by touching `src/icons/udpscope.gresource.xml` and rebuilding; any
+second warning is a finding. And an exit-dump run emits **no** `Gtk-CRITICAL` at all, nor any `Gtk-WARNING`: the dump's
 `gtk warnings:` line counts GTK's own log (through a writer function — GTK is built with structured
 logging, so the handler API never sees its messages) and must read `0`; see
 [probe-readings.md](probe-readings.md).
 
-An *incremental* build reads **one** of those three: the generated GResource `.c` is not recompiled
+An *incremental* build reads **zero**: the generated GResource `.c` is not recompiled
 when only `src/` changed, so its `-Woverlength-strings` does not reappear.
 
 A third reading every run offers for free: **how many `[udpscope] buffer allocated:` lines it
@@ -439,6 +437,15 @@ precedent, not an exception.
     levels `1.5, 2.5, 1.5` (the log prints the quantised voltage, so `1.4999, 2.4999, 1.4999` is the
     expected text), the DOUT bytes `0x00, 0x02, 0x00`, one `COUNTER_RESET`, one `DROP`;
   - **a rejected code:** mock `--code 1234`, app `code=7`: one error line, the retries stop.
+- `UDPSCOPE_PROBE_E1608_GEN=1500` with `UDPSCOPE_EXIT_AFTER_MS=5500`, run as `--source e1608 --source-opt
+  address=127.0.0.1 --source-opt port=54711 --source-opt ao0_init=0 --source-opt gen_rate=100` against
+  `tools/mock_e1608.py --port 54711 --log /tmp/e1608-gen100.log` -- the generator's update rate: it starts a Sine on
+  DAC 0 through the Analog out panel (and switches the side stack to that page, since the panel refreshes on its
+  frame clock, which does not tick for a page that is off screen), waits 2.5 s, reads the achieved rate and the
+  panel's "Update rate" row, stops the generator and reads both again 400 ms later. Two lines, in
+  `probe-readings.md`. Then count the mock log's `AOUT` lines: about 250 with `gen_rate=100` (the generator ran
+  for about 2.5 s) and about 125 for a run without the option (default 50 Hz). Short and serial, the mock killed
+  afterwards. It enables nothing else, so it can run alone.
 - `UDPSCOPE_PROBE_E1608_RECONNECT=8000` -- reads the source after the mock dropped the link and 500 ms
   later checks the frame count moved on. The reading's own entry is in `probe-readings.md`.
 - `UDPSCOPE_PROBE_E1608_SCAN=1000` with `UDPSCOPE_EXIT_AFTER_MS=6500`, run as `--source e1608 --source-opt
diff --git a/src/source/e1608/e1608_kind.cpp b/src/source/e1608/e1608_kind.cpp
index 9ba2d16..7d3d851 100644
--- a/src/source/e1608/e1608_kind.cpp
+++ b/src/source/e1608/e1608_kind.cpp
@@ -77,7 +77,7 @@ bool on_of(GtkWidget* w) { return adw_switch_row_get_active(ADW_SWITCH_ROW(w));
 /// closure shares; the raw widget pointers are valid while the chooser keeps the rows.
 struct Form {
   GtkWidget *address, *mac, *subnet, *port, *code, *timeout;
-  GtkWidget *rate, *ext_clock, *trigger, *auto_restart, *calibrate, *poll_rate;
+  GtkWidget *rate, *ext_clock, *trigger, *auto_restart, *calibrate, *poll_rate, *gen_rate;
   GtkWidget *mode, *ai[8], *ai_group;
   GtkWidget *dir[8], *do_init, *plot_counter, *ao_init[2];
   ChangeCb changed = std::make_shared<std::function<void()>>();
@@ -121,6 +121,7 @@ struct Form {
     c.set("auto_restart", on_of(auto_restart) ? "1" : "0");
     c.set("calibrate", on_of(calibrate) ? "1" : "0");
     c.set("poll_rate", num(value_of(poll_rate)));
+    c.set("gen_rate", num(value_of(gen_rate)));
     c.set("mode", diff() ? "diff" : "se");
     static const char* const kRange[] = {"", "BIP10V", "BIP5V", "BIP2V", "BIP1V"};
     for (int i = 0; i < 8; ++i) {
@@ -156,6 +157,7 @@ struct Form {
     adw_switch_row_set_active(ADW_SWITCH_ROW(auto_restart), s.auto_restart);
     adw_switch_row_set_active(ADW_SWITCH_ROW(calibrate), s.calibrate);
     adw_spin_row_set_value(ADW_SPIN_ROW(poll_rate), s.poll_rate);
+    adw_spin_row_set_value(ADW_SPIN_ROW(gen_rate), s.gen_rate);
     adw_combo_row_set_selected(ADW_COMBO_ROW(mode), s.diff ? 1 : 0);
     for (int i = 0; i < 8; ++i) {
       adw_combo_row_set_selected(
@@ -356,6 +358,7 @@ class E1608Kind final : public SourceKind {
     f->auto_restart = switch_row("_Restart after an overrun", true);
     f->calibrate = switch_row("Apply _factory calibration", true);
     f->poll_rate = spin_row("_Input poll rate (Hz)", 0.1, 100, 1, 10, 1);
+    f->gen_rate = spin_row("_Generator update rate (Hz)", 1, 200, 1, 50, 0);
     f->mode = combo_row("Input _mode", kMode);
     for (int i = 0; i < 8; ++i) {
       const std::string title = "Channel " + std::to_string(i);
@@ -384,7 +387,7 @@ class E1608Kind final : public SourceKind {
     GtkWidget* conn = expander("Connection", {f->scan_row, f->address, f->mac, f->subnet, f->port,
                                               f->code, f->timeout});
     GtkWidget* acq = expander("Acquisition", {f->rate, f->ext_clock, f->trigger, f->auto_restart,
-                                              f->calibrate, f->poll_rate});
+                                              f->calibrate, f->poll_rate, f->gen_rate});
     GtkWidget* ai = expander("Analog inputs", {f->mode, f->ai[0], f->ai[1], f->ai[2], f->ai[3],
                                                f->ai[4], f->ai[5], f->ai[6], f->ai[7]});
     GtkWidget* dio = expander("Digital I/O", {f->dir[0], f->dir[1], f->dir[2], f->dir[3], f->dir[4],
@@ -395,7 +398,7 @@ class E1608Kind final : public SourceKind {
 
     for (GtkWidget* w : {conn, acq, ai, dio}) hook_destroy(w, f);
     for (GtkWidget* w : {f->address, f->mac, f->subnet}) hook_entry(w, f);
-    for (GtkWidget* w : {f->port, f->code, f->timeout, f->rate, f->poll_rate, f->do_init,
+    for (GtkWidget* w : {f->port, f->code, f->timeout, f->rate, f->poll_rate, f->gen_rate, f->do_init,
                          f->ao_init[0], f->ao_init[1]})
       hook_notify(w, "notify::value", f);
     for (GtkWidget* w : {f->ext_clock, f->auto_restart, f->calibrate, f->plot_counter})
diff --git a/src/source/e1608/e1608_panels.cpp b/src/source/e1608/e1608_panels.cpp
index ecae53e..18408b3 100644
--- a/src/source/e1608/e1608_panels.cpp
+++ b/src/source/e1608/e1608_panels.cpp
@@ -55,7 +55,7 @@ void set_text(GtkWidget* label, const char* text) {
   if (std::strcmp(gtk_label_get_text(GTK_LABEL(label)), text) != 0) gtk_label_set_text(GTK_LABEL(label), text);
 }
 
-GtkWidget* panel_root(GtkWidget* a, GtkWidget* b = nullptr) {
+GtkWidget* panel_root(GtkWidget* a, GtkWidget* b = nullptr, GtkWidget* c = nullptr) {
   GtkWidget* box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 18);
   gtk_widget_set_margin_top(box, 12);
   gtk_widget_set_margin_bottom(box, 12);
@@ -63,6 +63,7 @@ GtkWidget* panel_root(GtkWidget* a, GtkWidget* b = nullptr) {
   gtk_widget_set_margin_end(box, 12);
   gtk_box_append(GTK_BOX(box), a);
   if (b != nullptr) gtk_box_append(GTK_BOX(box), b);
+  if (c != nullptr) gtk_box_append(GTK_BOX(box), c);
   return box;
 }
 
@@ -77,6 +78,7 @@ struct AoCtx {
   E1608Source* src = nullptr;
   std::shared_ptr<E1608Readouts> ro;
   AoWidgets w[2];
+  GtkWidget* gen_rate = nullptr;  ///< the "Update rate" row: the achieved rate against the requested one
   Hook hooks[2];
   bool updating = false;  ///< set while the panel writes its own widgets: those writes post nothing
   unsigned epoch_seen = 0;
@@ -148,6 +150,22 @@ void ao_refresh(AoCtx* c) {
     if (cur == nullptr || std::strcmp(cur, b) != 0)
       adw_action_row_set_subtitle(ADW_ACTION_ROW(c->w[ch].last), b);
   }
+
+  // The achieved generator rate: ticks completed per second, measured by the producer thread. Below
+  // the requested rate, the board's command latency is what limits it.
+  char r[64];
+  const double req = c->src->settings().gen_rate;
+  const bool running = c->ro->gen_on[0].load() || c->ro->gen_on[1].load();
+  const double hz = c->ro->gen_hz.load();
+  if (!running)
+    std::snprintf(r, sizeof r, "off (requested %.0f Hz)", req);
+  else if (hz <= 0.0)
+    std::snprintf(r, sizeof r, "measuring... (requested %.0f Hz)", req);
+  else
+    std::snprintf(r, sizeof r, "%.0f Hz (requested %.0f Hz)", hz, req);
+  const char* cur = adw_action_row_get_subtitle(ADW_ACTION_ROW(c->gen_rate));
+  if (cur == nullptr || std::strcmp(cur, r) != 0)
+    adw_action_row_set_subtitle(ADW_ACTION_ROW(c->gen_rate), r);
 }
 
 gboolean ao_tick(GtkWidget*, GdkFrameClock*, gpointer user) {
@@ -198,7 +216,15 @@ GtkWidget* build_ao(E1608Source* src) {
     ao_sensitivity(w);
   }
 
-  GtkWidget* root = panel_root(groups[0], groups[1]);
+  c->gen_rate = adw_action_row_new();
+  gtk_widget_set_name(c->gen_rate, "e1608-gen-rate");
+  adw_preferences_row_set_title(ADW_PREFERENCES_ROW(c->gen_rate), "Update rate");
+  adw_action_row_set_subtitle(ADW_ACTION_ROW(c->gen_rate), "off");
+  GtkWidget* gen_group = adw_preferences_group_new();
+  adw_preferences_group_set_title(ADW_PREFERENCES_GROUP(gen_group), "Generator");
+  adw_preferences_group_add(ADW_PREFERENCES_GROUP(gen_group), c->gen_rate);
+
+  GtkWidget* root = panel_root(groups[0], groups[1], gen_group);
   g_object_set_data_full(G_OBJECT(root), "e1608-ao-ctx", c,
                          +[](gpointer p) { delete static_cast<AoCtx*>(p); });
   gtk_widget_add_tick_callback(root, ao_tick, c, nullptr);
diff --git a/src/source/e1608/e1608_source.cpp b/src/source/e1608/e1608_source.cpp
index 7e85e95..fb66793 100644
--- a/src/source/e1608/e1608_source.cpp
+++ b/src/source/e1608/e1608_source.cpp
@@ -61,6 +61,7 @@ E1608Settings E1608Settings::from(const SourceConfig& c) {
   s.auto_restart = c.get_bool("auto_restart", true);
   s.calibrate = c.get_bool("calibrate", true);
   s.poll_rate = c.get_double("poll_rate", 10.0);
+  s.gen_rate = c.get_double("gen_rate", 50.0);
   s.diff = lower(c.get("mode", "se")) == "diff";
 
   bool any_key = false;
@@ -133,6 +134,7 @@ std::string E1608Settings::problem() const {
   }
   if (aggregate() < kMinAggregateHz) return "The aggregate rate must be at least 0.02 S/s";
   if (!(poll_rate >= 0.1 && poll_rate <= 100.0)) return "The input poll rate must be 0.1 to 100 Hz";
+  if (!(gen_rate >= 1.0 && gen_rate <= 200.0)) return "The generator update rate must be 1 to 200 Hz";
   return {};
 }
 
@@ -230,6 +232,7 @@ void E1608Source::fail(const std::string& msg, bool fatal) {
   any_gen_ = false;
   readouts_->gen_on[0].store(false);
   readouts_->gen_on[1].store(false);
+  gen_rate_reset();
   if (fatal) {
     state_ = State::Halted;
   } else {
@@ -327,7 +330,7 @@ void E1608Source::connect_and_start() {
   const auto now = Clock::now();
   next_slow_ = now;
   next_status_ = now + std::chrono::milliseconds(500);
-  next_gen_ = now + std::chrono::milliseconds(20);
+  next_gen_ = now + gen_period();
   slow_read();
 
   state_ = State::Scanning;
@@ -409,7 +412,7 @@ void E1608Source::run_timers() {
     check_status();
   }
   if (any_gen_ && now >= next_gen_) {
-    next_gen_ = now + std::chrono::milliseconds(20);
+    next_gen_ = now + gen_period();  // from now, not from the old deadline: a slow board gets no catch-up burst
     generator_tick(now);
   }
 }
@@ -475,22 +478,46 @@ void E1608Source::write_ao(int ch, double volts) {
   readouts_->ao[ch].store(dev_.aout(ch, volts, cal_));
 }
 
+E1608Source::Clock::duration E1608Source::gen_period() const {
+  return std::chrono::duration_cast<Clock::duration>(std::chrono::duration<double>(1.0 / cfg_.gen_rate));
+}
+
+void E1608Source::gen_rate_reset() {
+  gen_win_ticks_ = 0;
+  gen_win_t0_ = Clock::now();
+  readouts_->gen_hz.store(0.0);
+}
+
 void E1608Source::update_gen_flags() {
+  const bool was_gen = any_gen_;
   any_gen_ = false;
   for (int ch = 0; ch < 2; ++ch) {
     const bool on = ao_[ch].mode != AoMode::Level && ao_[ch].run;
     readouts_->gen_on[ch].store(on);
     any_gen_ = any_gen_ || on;
   }
+  if (any_gen_ != was_gen) gen_rate_reset();  // a generator started or the last one stopped
 }
 
 void E1608Source::generator_tick(Clock::time_point now) {
+  bool wrote = false;
   for (int ch = 0; ch < 2; ++ch) {
     const AoSettings& s = ao_[ch];
     if (s.mode == AoMode::Level || !s.run) continue;
     const double t = std::chrono::duration<double>(now - gen_t0_[ch]).count();
     const double phase = std::fmod(t * s.freq_hz, 1.0);
     write_ao(ch, clamp(s.offset + s.amplitude * wave(s.mode, phase), -10.0, 10.0));
+    wrote = true;
+  }
+  if (!wrote) return;
+  // The achieved rate: ticks that wrote, per second of wall time, published once a window closes.
+  // The DAC writes are synchronous, so a slow board shows up here as a rate below the requested one.
+  ++gen_win_ticks_;
+  const double elapsed = std::chrono::duration<double>(Clock::now() - gen_win_t0_).count();
+  if (elapsed >= 1.0) {
+    readouts_->gen_hz.store(gen_win_ticks_ / elapsed);
+    gen_win_ticks_ = 0;
+    gen_win_t0_ = Clock::now();
   }
 }
 
diff --git a/src/source/e1608/e1608_source.hpp b/src/source/e1608/e1608_source.hpp
index 81bb1e7..dfc7ad3 100644
--- a/src/source/e1608/e1608_source.hpp
+++ b/src/source/e1608/e1608_source.hpp
@@ -36,6 +36,7 @@ struct E1608Settings {
   bool auto_restart = true;
   bool calibrate = true;
   double poll_rate = 10.0;  ///< Hz, for the digital inputs and the counter
+  double gen_rate = 50.0;   ///< Hz, the waveform generator's DAC update rate
   bool diff = false;
   bool ai_on[8] = {};
   Range ai_range[8] = {};
@@ -62,6 +63,7 @@ struct E1608Readouts {
   std::atomic<std::uint32_t> counter{0};
   std::atomic<double> ao[2];            ///< the last DAC voltage written; NaN before any
   std::atomic<bool> gen_on[2];
+  std::atomic<double> gen_hz{0.0};      ///< generator ticks completed per second, over ~1 s; 0 when off
   std::atomic<unsigned> epoch{0};       ///< bumped at each (re)connect: panels re-sync from it
   E1608Readouts() {
     for (int i = 0; i < 2; ++i) {
@@ -117,6 +119,8 @@ class E1608Source final : public DataSource {
   void generator_tick(Clock::time_point now);
   void write_ao(int ch, double volts);
   void update_gen_flags();
+  void gen_rate_reset();
+  Clock::duration gen_period() const;
   void fail(const std::string& msg, bool fatal);
   void note(const std::string& msg);
   int wait_ms(int timeout_ms, Clock::time_point now) const;
@@ -153,6 +157,8 @@ class E1608Source final : public DataSource {
   AoSettings ao_[2];
   Clock::time_point gen_t0_[2];
   bool any_gen_ = false;
+  Clock::time_point gen_win_t0_;  ///< start of the current rate-measurement window
+  unsigned gen_win_ticks_ = 0;    ///< ticks that wrote since `gen_win_t0_`
 
   Clock::time_point retry_at_;
   Clock::time_point next_slow_, next_status_, next_gen_;
diff --git a/src/ui.cpp b/src/ui.cpp
index fe5c28d..c6c715d 100644
--- a/src/ui.cpp
+++ b/src/ui.cpp
@@ -3060,8 +3060,11 @@ void note_panel_controls(App& app) {
   // pill count reads 0 and the label count means nothing, rather than passing vacuously.
   int pills = 0;
   int drawn_labels = 0;
+  int drawn_images = 0;
   const std::function<void(GtkWidget*)> count_drawn = [&](GtkWidget* w) {
     if (GTK_IS_TOGGLE_BUTTON(w) && gtk_widget_get_mapped(w)) ++pills;
+    // A *mapped* image is an icon (or its missing-icon placeholder) on a tab: tabs are words only.
+    if (GTK_IS_IMAGE(w) && gtk_widget_get_mapped(w)) ++drawn_images;
     // A *mapped* label with text: an empty label would be counted by "mapped" alone.
     if (GTK_IS_LABEL(w) && gtk_widget_get_mapped(w) && gtk_label_get_text(GTK_LABEL(w))[0] != '\0') {
       ++drawn_labels;
@@ -3074,6 +3077,7 @@ void note_panel_controls(App& app) {
   if (app.side_switcher != nullptr) count_drawn(app.side_switcher);
   app.dbg_switcher_pills = pills;
   app.dbg_switcher_labels = drawn_labels;
+  app.dbg_switcher_images = drawn_images;
   // Walked through `get_pages()`, not the widget tree: an `AdwViewStackPage` is a plain `GObject`.
   app.dbg_switcher_pages =
       app.side_stack != nullptr
@@ -5203,7 +5207,9 @@ void on_activate(GtkApplication* application, gpointer user) {
                      G_CALLBACK(on_side_tab_changed), app);
   }
   // The source kind's own tabs (a generator, digital I/O), added before the first tick so the
-  // pages-versus-pills reading below counts them too.
+  // pages-versus-pills reading below counts them too. The tabs are words, so the switcher's icons
+  // are hidden first and kept hidden for the pages this call adds.
+  keep_tabs_icon_free(*app);
   build_source_panels(*app);
 
   // The left side is the events pane *and* the plot, in one row: the pane is a column of its own
@@ -6028,6 +6034,9 @@ int run_ui(int argc, char** argv, const Config& cfg, ScopeModel& model, Acquisit
   if (const char* env = g_getenv("UDPSCOPE_PROBE_E1608")) {
     g_timeout_add(static_cast<guint>(std::atoi(env)), e1608_probe, &app);
   }
+  if (const char* env = g_getenv("UDPSCOPE_PROBE_E1608_GEN")) {
+    g_timeout_add(static_cast<guint>(std::atoi(env)), e1608_gen_probe, &app);
+  }
   if (const char* env = g_getenv("UDPSCOPE_PROBE_E1608_RECONNECT")) {
     g_timeout_add(static_cast<guint>(std::atoi(env)), e1608_probe_reconnect, &app);
   }
@@ -6240,10 +6249,10 @@ int run_ui(int argc, char** argv, const Config& cfg, ScopeModel& model, Acquisit
                 app.dbg_panel_switch_trigger, app.dbg_toolbar_switch_trigger,
                 app.dbg_panel_switch_cursors, app.dbg_toolbar_switch_cursors,
                 app.dbg_panel_drove_toolbar);
-    std::printf("[udpscope]   switcher: policy=%s pills=%d labels=%d pages=%d size=%dx%d\n",
+    std::printf("[udpscope]   switcher: policy=%s pills=%d labels=%d images=%d pages=%d size=%dx%d\n",
                 app.dbg_switcher_policy == 0 ? "narrow" : (app.dbg_switcher_policy == 1 ? "wide" : "?"),
-                app.dbg_switcher_pills, app.dbg_switcher_labels, app.dbg_switcher_pages,
-                app.dbg_switcher_w, app.dbg_switcher_h);
+                app.dbg_switcher_pills, app.dbg_switcher_labels, app.dbg_switcher_images,
+                app.dbg_switcher_pages, app.dbg_switcher_w, app.dbg_switcher_h);
     // The help affordance layer: what the contextual-help toggle left on the surfaces, and where the
     // guided tour stood when the last capture ran. Both are captured on the tick (`capture_help_state`),
     // so neither asks a destroyed widget anything.
diff --git a/src/ui_app.hpp b/src/ui_app.hpp
index 95852f4..8437d53 100644
--- a/src/ui_app.hpp
+++ b/src/ui_app.hpp
@@ -444,6 +444,9 @@ struct App {
   /// are words (`wide` policy, a title per page), so the label count must equal the page count.
   int dbg_switcher_pills = -1;
   int dbg_switcher_labels = -1;
+  /// How many `GtkImage`s the switcher has *mapped*: a tab is its title and nothing else, so this
+  /// must be 0 -- an icon, or the missing-icon placeholder GTK draws for a page with no `icon-name`.
+  int dbg_switcher_images = -1;
   /// How many pages the sidebar stack holds: `pills` and `labels` must both equal it.
   int dbg_switcher_pages = -1;
   /// The switcher's own size, beside it: what the tab bar costs the column.
@@ -1560,6 +1563,11 @@ void config_dialog_refresh(ConfigDialog& d);
 void open_configurations(App& app);
 void save_layout_now(App& app);
 
+/// The sidebar's tabs are words: hide the icon every `AdwViewSwitcherButton` draws (the
+/// missing-icon placeholder, for a page with a title and no `icon-name`), for the buttons that exist
+/// and for any page added later. Call once, before `build_source_panels()`.
+void keep_tabs_icon_free(App& app);
+
 /// Capability panels (`src/ui_source.cpp`). `build_source_panels` adds the source kind's panels as
 /// pages of `side_stack`, once, before the first tick. `apply_source_panels` sets every panel's
 /// sensitivity from `connected` -- disabled, never hidden: the tab switcher owns visibility.
@@ -1873,6 +1881,12 @@ gboolean e1608_probe(gpointer user);
 gboolean e1608_probe_report(gpointer user);
 gboolean e1608_probe_reconnect(gpointer user);
 gboolean e1608_probe_resumed(gpointer user);
+/// The generator's update rate: starts a Sine on DAC 0 through the panel, reads the achieved rate the
+/// source measured and the Analog out panel's "Update rate" row (`_report`, 2.5 s later), then stops
+/// it and checks both read "off" (`_stopped`).
+gboolean e1608_gen_probe(gpointer user);
+gboolean e1608_gen_probe_report(gpointer user);
+gboolean e1608_gen_probe_stopped(gpointer user);
 /// The E-1608 form's "Scan network" row: presses Scan against the mock, then (phases `_fill`,
 /// `_rescan`) clicks a result to fill the address, "Use MAC" to fill the MAC, scans again and checks
 /// the results were replaced, not added to.
diff --git a/src/ui_probe.cpp b/src/ui_probe.cpp
index bb334b2..fe5dc8c 100644
--- a/src/ui_probe.cpp
+++ b/src/ui_probe.cpp
@@ -467,7 +467,7 @@ gboolean math_probe(gpointer user) {
   MathChannel gain;
   gain.name = "math x2";
   gain.enabled = true;
-  gain.nodes = {MathNode{MathOp::Source, name}, MathNode{MathOp::Gain}};
+  gain.nodes = {MathNode{MathOp::Source, name}, MathNode{MathOp::Gain, {}}};
   gain.nodes[1].in_a = 0;
   gain.nodes[1].gain = 2.0;
   gain.output = 1;
@@ -476,14 +476,14 @@ gboolean math_probe(gpointer user) {
   MathChannel lp;
   lp.name = "math lp";
   lp.enabled = true;
-  lp.nodes = {MathNode{MathOp::Source, late_name}, MathNode{MathOp::LowPass}};
+  lp.nodes = {MathNode{MathOp::Source, late_name}, MathNode{MathOp::LowPass, {}}};
   lp.nodes[1].in_a = 0;
   lp.nodes[1].fc = 20.0;
   lp.output = 1;
   channels.push_back(lp);
 
   // A third channel so the editor's new form row is built and synced on a baseline run. Assigned field
-  // by field: a partial brace-initialiser would add a fifth build warning.
+  // by field: a partial brace-initialiser would add a build warning.
   MathChannel dn;
   dn.name = "math denoise";
   dn.enabled = true;
@@ -1269,8 +1269,8 @@ gboolean mathwrap_probe(gpointer user) {
   MathChannel gain;
   gain.name = "math wrap";
   gain.enabled = true;
-  // Field by field: a partial brace-initialiser would add a fourth build warning, and the baseline
-  // is exactly three.
+  // Field by field: a partial brace-initialiser would add a build warning, and the baseline
+  // is exactly one on a clean build.
   MathNode src;
   src.op = MathOp::Source;
   src.source = name;
@@ -1923,6 +1923,7 @@ gboolean source_kinds_probe(gpointer user) {
       c.set("trigger", "rising");
       c.set("dir1", "o");
       c.set("plot0", "1");
+      c.set("gen_rate", "120");
     } else if (id == "flatudp") {
       c.set("port", "44600");
       c.set("bind", "10.0.0.8");
@@ -2428,6 +2429,76 @@ gboolean e1608_probe(gpointer user) {
   return G_SOURCE_REMOVE;
 }
 
+/// Phase 3 of the generator probe: the generator switched off 400 ms ago; the achieved rate and the
+/// panel must both have gone back to "off".
+gboolean e1608_gen_probe_stopped(gpointer user) {
+  App* a = static_cast<App*>(user);
+  if (a->window == nullptr) return G_SOURCE_REMOVE;
+  e1608::E1608Source* src = e1608_source(a);
+  if (src == nullptr) return G_SOURCE_REMOVE;
+  GtkWidget* row = find_named(source_panel_content(a, "source-ao"), "e1608-gen-rate");
+  const char* sub = row != nullptr ? adw_action_row_get_subtitle(ADW_ACTION_ROW(row)) : nullptr;
+  const double hz = src->readouts()->gen_hz.load();
+  const bool off = sub != nullptr && std::strncmp(sub, "off", 3) == 0;
+  std::fprintf(stderr, "[e1608] generator stopped: achieved=%.1f panel='%s' ok=%d\n", hz,
+               sub != nullptr ? sub : "", hz == 0.0 && off ? 1 : 0);
+  std::fflush(stderr);
+  return G_SOURCE_REMOVE;
+}
+
+/// Phase 2 of the generator probe, 2.5 s after a Sine generator was started on DAC 0: the achieved
+/// update rate the source measured, and the text the Analog out panel shows for it.
+gboolean e1608_gen_probe_report(gpointer user) {
+  App* a = static_cast<App*>(user);
+  if (a->window == nullptr) return G_SOURCE_REMOVE;
+  e1608::E1608Source* src = e1608_source(a);
+  if (src == nullptr) return G_SOURCE_REMOVE;
+  GtkWidget* ao = source_panel_content(a, "source-ao");
+  GtkWidget* row = find_named(ao, "e1608-gen-rate");
+  const char* sub = row != nullptr ? adw_action_row_get_subtitle(ADW_ACTION_ROW(row)) : nullptr;
+  const double req = src->settings().gen_rate;
+  const double hz = src->readouts()->gen_hz.load();
+  // The mock answers at once, so the achieved rate sits at the requested one; the band is loose.
+  const bool in_range = hz >= 0.7 * req && hz <= 1.1 * req;
+  char want[32];
+  std::snprintf(want, sizeof want, "(requested %.0f Hz)", req);
+  const bool shown = sub != nullptr && std::strstr(sub, want) != nullptr && std::strstr(sub, "Hz") != nullptr;
+  std::fprintf(stderr, "[e1608] generator: requested=%.1f achieved=%.1f panel='%s' ok=%d\n", req, hz,
+               sub != nullptr ? sub : "", in_range && shown ? 1 : 0);
+  std::fflush(stderr);
+  GtkWidget* run = find_named(ao, "e1608-ao0-run");
+  if (run != nullptr) adw_switch_row_set_active(ADW_SWITCH_ROW(run), FALSE);
+  g_timeout_add(400, e1608_gen_probe_stopped, a);
+  return G_SOURCE_REMOVE;
+}
+
+/// Starts a Sine generator on DAC 0 through the panel's own controls, then reads it 2.5 s later.
+gboolean e1608_gen_probe(gpointer user) {
+  App* a = static_cast<App*>(user);
+  if (a->window == nullptr) return G_SOURCE_REMOVE;
+  e1608::E1608Source* src = e1608_source(a);
+  if (src == nullptr) {
+    std::fprintf(stderr, "[e1608] generator: no e1608 source (run with --source e1608)\n");
+    std::fflush(stderr);
+    return G_SOURCE_REMOVE;
+  }
+  GtkWidget* ao = source_panel_content(a, "source-ao");
+  GtkWidget* mode = find_named(ao, "e1608-ao0-mode");
+  GtkWidget* run = find_named(ao, "e1608-ao0-run");
+  if (mode == nullptr || run == nullptr) {
+    std::fprintf(stderr, "[e1608] generator: controls missing (mode=%d run=%d)\n", mode != nullptr ? 1 : 0,
+                 run != nullptr ? 1 : 0);
+    std::fflush(stderr);
+    return G_SOURCE_REMOVE;
+  }
+  // The panel refreshes on its frame clock, which only ticks while the page is on screen.
+  if (a->side_stack != nullptr) adw_view_stack_set_visible_child_name(ADW_VIEW_STACK(a->side_stack), "source-ao");
+  adw_combo_row_set_selected(ADW_COMBO_ROW(mode), 1);  // Sine
+  adw_switch_row_set_active(ADW_SWITCH_ROW(run), TRUE);
+  g_timeout_add(2500, e1608_gen_probe_report, a);
+  return G_SOURCE_REMOVE;
+}
+
 /// After the mock dropped the link: has the source reconnected, and does the stream move again?
 gboolean e1608_probe_resumed(gpointer user) {
   App* a = static_cast<App*>(user);
@@ -5843,9 +5914,8 @@ int noise_channel(App* a, const char* name) {
 // the older feature's proof, so the new channel stays out of the acquisition plan until they have
 // all run, and only the de-noise comparison is taken with it in.
 //
-// Fields assigned rather than brace-initialised: a partial brace-initialiser on `MathNode` is
-// what the two `-Wmissing-field-initializers` in this file already are, and the build baseline
-// is exactly four warnings.
+// Fields assigned rather than brace-initialised: a partial brace-initialiser on `MathNode` leaves
+// `source` out and warns (`-Wmissing-field-initializers`), and the build baseline is one warning.
 gboolean noise_probe_setup(gpointer user) {
   App* a = static_cast<App*>(user);
   if (a->window == nullptr) return G_SOURCE_REMOVE;
diff --git a/src/ui_source.cpp b/src/ui_source.cpp
index d81b723..d880485 100644
--- a/src/ui_source.cpp
+++ b/src/ui_source.cpp
@@ -11,6 +11,48 @@
 namespace udpscope {
 namespace ui_impl {
 
+namespace {
+
+/// Hide every `GtkImage` inside `w`, and keep it hidden. `AdwViewSwitcherButton` always builds an
+/// icon -- in both of its layouts -- and a page with no `icon-name` gets `image-missing`, which is
+/// the placeholder the sidebar's text tabs used to draw. There is no property or policy that turns
+/// the icon off, so the image is hidden (a hidden child takes no space: the label gets the pill) and
+/// a `notify::visible` handler puts it back to hidden if the button ever shows it again.
+void hide_tab_icons(GtkWidget* w) {
+  if (GTK_IS_IMAGE(w)) {
+    if (g_object_get_data(G_OBJECT(w), "udpscope-icon-hidden") == nullptr) {
+      g_object_set_data(G_OBJECT(w), "udpscope-icon-hidden", GINT_TO_POINTER(1));
+      g_signal_connect(w, "notify::visible", G_CALLBACK(+[](GObject* o, GParamSpec*, gpointer) {
+                         GtkWidget* img = GTK_WIDGET(o);
+                         if (gtk_widget_get_visible(img)) gtk_widget_set_visible(img, FALSE);
+                       }),
+                       nullptr);
+    }
+    gtk_widget_set_visible(w, FALSE);
+    return;
+  }
+  for (GtkWidget* c = gtk_widget_get_first_child(w); c != nullptr; c = gtk_widget_get_next_sibling(c)) {
+    hide_tab_icons(c);
+  }
+}
+
+void on_tab_pages_changed(GListModel*, guint, guint, guint, gpointer sw) {
+  hide_tab_icons(GTK_WIDGET(sw));
+}
+
+}  // namespace
+
+void keep_tabs_icon_free(App& app) {
+  if (app.side_switcher == nullptr || app.side_stack == nullptr) return;
+  hide_tab_icons(app.side_switcher);
+  // A page added later gets a button when the model reports it; this handler is connected *after*
+  // the switcher's own, so the button already exists when it runs.
+  g_signal_connect_after(adw_view_stack_get_pages(ADW_VIEW_STACK(app.side_stack)), "items-changed",
+                         G_CALLBACK(on_tab_pages_changed), app.side_switcher);
+  // And once more when the switcher is (re)mapped, which also covers a rebuild of the buttons.
+  g_signal_connect_swapped(app.side_switcher, "map", G_CALLBACK(hide_tab_icons), app.side_switcher);
+}
+
 void build_source_panels(App& app) {
   if (app.side_stack == nullptr || app.acq == nullptr || app.acq->source() == nullptr) return;
   SourceKind* kind = find_kind(app.source_kind);