Bug 275171 [Contributions] Customize Perspective action breaks editor pinning action
Using M7, I enabled editor pinning (i.e. Reuse editor) and pinned an editor using an action in the toolbar. I then disabled editor pinning ad then opened the customized perspective dialog. After this, enabling/disabling editor pinning does not make the Pin Editor action reappear.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/WorkbenchActionBuilder.java
/**
	 * Creates and returns the Help menu.
	 */
	private MenuManager createHelpMenu() {
		MenuManager menu = new MenuManager(IDEWorkbenchMessages.Workbench_help, IWorkbenchActionConstants.M_HELP);
		addSeparatorOrGroupMarker(menu, "group.intro"); 
		
		if (introAction != null) {
			menu.add(introAction);
		} else if (quickStartAction != null) {
			menu.add(quickStartAction);
		}
		menu.add(new GroupMarker("group.intro.ext")); 
		addSeparatorOrGroupMarker(menu, "group.main"); 
		menu.add(helpContentsAction);
        menu.add(helpSearchAction);
		menu.add(dynamicHelpAction);
		addSeparatorOrGroupMarker(menu, "group.assist"); 
		
		if (tipsAndTricksAction != null) {
			menu.add(tipsAndTricksAction);
		}
		
		
		menu.add(new GroupMarker(IWorkbenchActionConstants.HELP_START));
		menu.add(new GroupMarker("group.main.ext")); 
		addSeparatorOrGroupMarker(menu, "group.tutorials"); 
		addSeparatorOrGroupMarker(menu, "group.tools"); 
		addSeparatorOrGroupMarker(menu, "group.updates"); 
		menu.add(new GroupMarker(IWorkbenchActionConstants.HELP_END));