Inspector symbol chooser tooltip lingers over the picker window

In Studio's inspector, the "…" button next to the System Symbol row keeps its tooltip ("Choose system symbol…") while the "Choose System Symbol" picker window is open. The lingering tooltip can then appear over the main window and flicker over the picker window as the mouse moves across it.

Expected behaviour: a control whose window is disabled by an open dialog should not show a tooltip, and any tooltip that was open when the dialog appeared should close.

User impact is visual glitching around the symbol picker. There is no data loss or crash.