[akurtakov]

GTK sends the focus leave events walking up the widget tree from the old focus widget. A popup disposed by a FocusOut listener was popped down and unparented in the middle of that walk, and GTK looped forever on the destroyed widgets.

Queue a popover disposed while a focus callback runs and destroy it after the focus change, from an asyncExec that waits while a listener still runs a nested event loop.

Assisted-by: Anthropic Claude Code (claude-opus-5-5)

[github-actions]

Test Results

 1 026 files  ±0   1 026 suites  ±0   1h 37m 16s ⏱️ + 17m 34s
 5 067 tests +1   5 039 ✅ +1     28 💤 ±0  0 ❌ ±0 
29 761 runs  +6  27 225 ✅ +6  2 536 💤 ±0  0 ❌ ±0 

Results for commit 5abb709. ± Comparison against base commit e147461.

[Copilot]

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Copilot review overview

3 open issues

• As shown, scrollProc(...) has a boolean return type but now contains return; with no value,… · New
• When !isDisposed() is false, the deferred cleanup is intentionally not scheduled, but… · New
• The PR description and implementation are explicitly GTK4-specific (popover/focus-dispatch… · New

What changed in this PR

Fixes a GTK4 focus-change edge case where disposing a popover during FocusOut can cause GTK to loop on destroyed widgets, by deferring popover teardown until after focus dispatch completes.

Changes:

• Add a regression test that disposes an ON_TOP child shell during FocusOut.
• Defer gtk_popover_popdown()/gtk_widget_unparent() for popovers disposed inside focus dispatch, and perform the destruction later via asyncExec.
• Track focus-dispatch depth and queue popover handles for deferred destruction.

File	Description
tests/​org.eclipse.swt.tests/​JUnit Tests/​org/​eclipse/​swt/​tests/​junit/​Test_org_eclipse_swt_widgets_Shell.java	Adds a regression test that disposes a popup on FocusOut and waits for disposal completion.
bundles/​org.eclipse.swt/​Eclipse SWT/​gtk/​org/​eclipse/​swt/​widgets/​Shell.java	Defers popover popdown/unparent when a shell is released during focus dispatch.
bundles/​org.eclipse.swt/​Eclipse SWT/​gtk/​org/​eclipse/​swt/​widgets/​Display.java	Adds focus-dispatch depth tracking and deferred popover destruction via asyncExec.

_{Review effort: Lite}