The global left-click listener fires PropPointerPressed on every mouse
press anywhere in the app, and the handler used to launch a full
widget-tree focus sweep on each one - even when the Properties panel
was closed. Gate the sweep on dock_panel_visible(Properties): when the
panel is hidden the handler now returns Task::none, turning an O(whole
UI) traversal per click into an O(1) boolean check in the common case.
The other sweep call sites already gate via sync_active_field_if_any;
this was the only ungated one.
Tests:
- hidden_properties_panel_skips_the_focus_sweep - a click with the
panel closed returns a Task::none (units == 0), i.e. no sweep.
- visible_properties_panel_runs_the_focus_sweep - a click with the
panel open still fires the sweep (units > 0), preserving the
select-whole-value behavior.
eead4eb5f0