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
IDEActionFactory.BOOKMARK.getCommandId(),
				null, null, IDEWorkbenchMessages.Workbench_addBookmark,
				IDEWorkbenchMessages.Workbench_addBookmarkToolTip, null);
	}
    
    private IContributionItem getTaskItem() {
		return getItem(
				IDEActionFactory.ADD_TASK.getId(),
				IDEActionFactory.ADD_TASK.getCommandId(),
				null, null, IDEWorkbenchMessages.Workbench_addTask,
				IDEWorkbenchMessages.Workbench_addTaskToolTip, null);
	}
    
    private IContributionItem getDeleteItem() {
        return getItem(ActionFactory.DELETE.getId(),
        		ActionFactory.DELETE.getCommandId(),
        		ISharedImages.IMG_TOOL_DELETE,
        		ISharedImages.IMG_TOOL_DELETE_DISABLED,
        		WorkbenchMessages.Workbench_delete,
        		WorkbenchMessages.Workbench_deleteToolTip, 
        		IWorkbenchHelpContextIds.DELETE_RETARGET_ACTION);
    }
    
    private IContributionItem getRevertItem() {
		return getItem(
				ActionFactory.REVERT.getId(),
				ActionFactory.REVERT.getCommandId(),
				null, null, WorkbenchMessages.Workbench_revert,
				WorkbenchMessages.Workbench_revertToolTip, null);
	}