Revert "Fix race condition in CleanupAddon.subscribeRenderingChanged"

This reverts commit 54b8aa2.

Author: trancexpress

bundles/org.eclipse.e4.ui.workbench.addons.swt/src/org/eclipse/e4/ui/workbench/addons/cleanupaddon/CleanupAddon.java

@@ -346,13 +346,16 @@ private void subscribeRenderingChanged(
 				int visCount = modelService.countRenderableChildren(container);
 
 				// Remove stacks with no visible children from the display (but not the
-				// model). Since event delivery is synchronous (EventBroker.send via
-				// EventAdmin.sendEvent and Display.syncExec), the visCount reflects
-				// the actual state at the time of this event and can be acted upon
-				// immediately without deferring via asyncExec.
-				if (visCount == 0 && !isLastEditorStack(container)) {
-					container.setToBeRendered(false);
-					transferPrimaryDataStackIfRemoved(container);
+				// model)
+				final MElementContainer<MUIElement> theContainer = container;
+				if (visCount == 0) {
+					Display.getCurrent().asyncExec(() -> {
+						int visCount1 = modelService.countRenderableChildren(theContainer);
+						if (!isLastEditorStack(theContainer) && visCount1 == 0) {
+							theContainer.setToBeRendered(false);
+							transferPrimaryDataStackIfRemoved(theContainer);
+						}
+					});
 				} else if (container.getParent() != null) { // omit detached windows
 					// if there are rendered elements but none are 'visible' we should
 					// make the container invisible as well

tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/workbench/PartRenderingEngineTests.java

@@ -64,6 +64,7 @@
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.widgets.ToolBar;
 import org.eclipse.swt.widgets.Widget;
+import org.eclipse.ui.tests.harness.util.DisplayHelper;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Disabled;
@@ -2446,9 +2447,12 @@ public void ensureCleanUpAddonCleansUp() {
 		assertTrue(partStackForPartBPartC.isToBeRendered(), " PartStack with children should be rendered");
 		partService.hidePart(partB);
 		partService.hidePart(partC);
-		contextRule.spinEventLoop();
-		assertFalse(partStackForPartBPartC.isToBeRendered(),
-				"CleanupAddon should ensure that partStack is not rendered anymore, as all childs have been removed");
+		// DisplayHelper.waitForCondition() handles event processing via Display.sleep()
+		// and retries. Calling spinEventLoop() here creates a race condition where
+		// events may be processed before CleanupAddon's asyncExec() is queued (line 352).
+		assertTrue(
+				DisplayHelper.waitForCondition(Display.getDefault(), 30_000,
+						() -> !partStackForPartBPartC.isToBeRendered()), "CleanupAddon should ensure that partStack is not rendered anymore, as all childs have been removed");
 		// PartStack with IPresentationEngine.NO_AUTO_COLLAPSE should not be removed
 		// even if children are removed
 		partService.hidePart(editor, true);