help: the search block's (i) on its header, a 12 px mark, and a real search page

src/ui_probe.cpp

@@ -4773,6 +4773,24 @@ gboolean helpui_probe_step(gpointer user) {
     helpui_probe_next(*a, 8, 400);
     return G_SOURCE_REMOVE;
   }
+  // The search block's "(i)" rides the expander's *header* box, which is in the widget tree and on
+  // screen while the block is collapsed -- unlike the expander's child, which is out of the
+  // widget-parent chain until it is expanded (see the invariant). Read here, in config mode with the
+  // pane and the sidebar up and the block still collapsed: `mapped=1` and a real size *on a collapsed
+  // expander* is the whole point, and a hint hung on the child would read 0x0 here.
+  if (a->trigger_search != nullptr) {
+    GtkWidget* hint = gtk_widget_get_last_child(a->trigger_search);
+    int sw = 0;
+    int sh = 0;
+    context_help_size_in(hint, &sw, &sh);
+    std::fprintf(stderr,
+                 "[helpui] collapsed search: expanded=%d mapped=%d mapped_header=%d hint=%dx%d\n",
+                 a->search_exp != nullptr && gtk_expander_get_expanded(GTK_EXPANDER(a->search_exp))
+                     ? 1
+                     : 0,
+                 hint != nullptr && gtk_widget_get_mapped(hint) ? 1 : 0,
+                 gtk_widget_get_mapped(a->trigger_search) ? 1 : 0, sw, sh);
+  }
   std::fflush(stderr);
   return G_SOURCE_REMOVE;
 }