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
if (resourceListener != null) {
            ResourcesPlugin.getWorkspace().removeResourceChangeListener(resourceListener);
            resourceListener = null;
        }
        pinEditorContributionItem.dispose();
        showInQuickMenu.dispose();
        newQuickMenu.dispose();
        
        
        closeAction = null;
        closeAllAction = null;
        closeAllSavedAction = null;
        closeOthersAction = null;
        saveAction = null;
        saveAllAction = null;
        newWindowAction = null;
		newEditorAction = null;
        helpContentsAction = null;
        helpSearchAction = null;
		dynamicHelpAction = null;
        aboutAction = null;
        openPreferencesAction = null;
        saveAsAction = null;
        hideShowEditorAction = null;
        savePerspectiveAction = null;
        resetPerspectiveAction = null;
        editActionSetAction = null;
        closePerspAction = null;
        lockToolBarAction = null;
        closeAllPerspsAction = null;