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
Shell shell = window.getShell();
	        if (shell != null && !shell.isDisposed()) {
        		shell.getDisplay().asyncExec(update);
	        }
        }
    }
	/**
     * Update the pin action's tool bar
     */
    void updatePinActionToolbar() {
        ICoolBarManager coolBarManager = getActionBarConfigurer()
                .getCoolBarManager();
        IContributionItem cbItem = coolBarManager
                .find(IWorkbenchActionConstants.TOOLBAR_NAVIGATE);
        if (!(cbItem instanceof IToolBarContributionItem)) {
            
            IDEWorkbenchPlugin
                    .log("Navigation toolbar contribution item is missing"); 
            return;
        }
        IToolBarContributionItem toolBarItem = (IToolBarContributionItem) cbItem;
        IToolBarManager toolBarManager = toolBarItem.getToolBarManager();
        if (toolBarManager == null) {
            
            IDEWorkbenchPlugin.log("Navigate toolbar is missing"); 
            return;
        }
        toolBarManager.update(false);
        toolBarItem.update(ICoolBarManager.SIZE);
    }