A scope or detached window drew its traces and nothing else: no cursors, no gate band, no trigger
marker, no measurement marks. They are not per-window state to be recreated -- the cursors are one
pair of times, the gate one band, the trigger one instant -- so the main window's row set stays the
**owner** and every window is written from it.
`sync_scope_instruments()` runs in the main tick after the main's own `sync_cursors()`/
`sync_gate()`: a gesture inside a scope window is read back from *that* window's controllers first
(those two calls only adopt while their own plot holds the grab, which is exactly "the drag
happened here"), adopted by the owner, and then every window -- the dragged one included -- is
written from the owner with the same cursor pair, mode and visibility, gate bounds and visibility,
and trigger marker. `RowSet::set_cursors()` is the new pair setter; `trigger_marker_x()`/`_visible()`
are the getters the mirror reads. The measurement marks travel by signal name
(`RowSet::MeasureMark::signal`, filled by the measures pass), so each window finds the row that
plots the signal and draws its ruler or mark there -- or none, when it does not plot it. The search
marks are times on the window and are placed on every window by the same per-frame path, and the
crosshair-axis-labels preference is restated to open windows when it changes.
Probe: `[scope-probe] instruments windows=N cursors=N gate=N trigger=N marks=N (main trigger
on=..)`, after adding a real gated `Top` measurement on `sine` -- the gate is restated visible each
frame by `update_measures()` and marks come only from `show_on_plot` measurements, so the leg uses
the app's own path. Docs: README, the cursors invariant, and the probe readings.
Martino Ferrari
91ca29d181