Bug 94456 [Undo] - Resource Navigator not showing workspace undo actions
The Resource Navigator is not showing the workspace undo actions. Package Explorer is correctly working. Need to look at the difference in the way the action handlers are set up.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/navigator/ResourceNavigator.java
public boolean isLinkingEnabled() {
        return linkingEnabled;
    }
    /**
     * Brings the corresponding editor to top if the selected resource is open.
     * 
     * @since 2.0
     */
    protected void linkToEditor(IStructuredSelection selection) {
        Object obj = selection.getFirstElement();
        if (obj instanceof IFile && selection.size() == 1) {
            IFile file = (IFile) obj;
            IWorkbenchPage page = getSite().getPage();
            IEditorPart editor = ResourceUtil.findEditor(page, file);
            if (editor != null) {
                page.bringToTop(editor);
                return;
            }
        }   
    }
    /**
     * Creates the action group, which encapsulates all actions for the view.
     * Installs global action handlers for undo and redo.
     */
    protected void makeActions() {
        setActionGroup(new MainActionGroup(this));
        createGlobalActionHandlers();
    }
    /**
     * Migrates the dialog settings from the UI plugin store to the