FindReplaceOverlay: avoid exception while closing workbench window #2666

When closing a workbench window while a find/replace overlay is open and
one of the input fields (find/replace) has focus, an exception is
thrown. This is caused by the FindReplaceOverlay trying to reactive
shortcuts of the underlying editor while the input field is losing
focus, but the handler service to perform the activation in is already
disposed.

Since there is no direct way of determining the underlying handler
service from the overlay to identify whether it is already disposed,
this change makes the overlay simply check for the workbench window
currently being closed. This is reasonable as the reactivation of
handlers is unnecessary if the underlying window is closed anyway.

Fixes #2666

Author: HeikoKlare

bundles/org.eclipse.ui.workbench.texteditor/src/org/eclipse/ui/internal/findandreplace/overlay/FindReplaceOverlay.java

@@ -172,7 +172,7 @@ public void focusLost(FocusEvent e) {
 		 * boolean)
 		 */
 		private void setTextEditorActionsActivated(boolean state) {
-			if (!(targetPart instanceof AbstractTextEditor)) {
+			if (!(targetPart instanceof AbstractTextEditor) || targetPart.getSite().getWorkbenchWindow().isClosing()) {
 				return;
 			}
 			if (targetPart.getSite() instanceof MultiPageEditorSite multiEditorSite) {