Bug 34769 [Navigator] F2/F5 actions not enabled/disabled properly when closing/opening project
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/navigator/MainActionGroup.java
workspaceGroup.fillActionBars(actionBars);
		
		IMenuManager menu = actionBars.getMenuManager();
		menu.add(toggleLinkingAction);
		
		IToolBarManager toolBar = actionBars.getToolBarManager();
		toolBar.add(new Separator());
		toolBar.add(collapseAllAction);		
		toolBar.add(toggleLinkingAction);
	}
	
	/**
	 * Updates the actions which were added to the action bars,
	 * delegating to the subgroups as necessary.
	 */
	public void updateActionBars() {
		IStructuredSelection selection =
			(IStructuredSelection) getContext().getSelection();
		propertyDialogAction.setEnabled(selection.size() == 1);
		addBookmarkAction.selectionChanged(selection);
		addTaskAction.selectionChanged(selection);		
		
		gotoGroup.updateActionBars();
		openGroup.updateActionBars();
		refactorGroup.updateActionBars();
		workingSetGroup.updateActionBars();
		sortAndFilterGroup.updateActionBars();
		workspaceGroup.updateActionBars();
	}