Bug 75711 AstProvider should not create AST if requested by SelectionListenerWithASTManager
3.1 M2 If SelectionListenerWithASTManager waits for an AST and the editor closes we should not create an AST for that one but return null instead.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
stores.add(JavaPlugin.getDefault().getPreferenceStore());
		stores.add(new PreferencesAdapter(JavaCore.getPlugin().getPluginPreferences()));
		stores.add(EditorsUI.getPreferenceStore());
		
		return new ChainedPreferenceStore((IPreferenceStore[]) stores.toArray(new IPreferenceStore[stores.size()]));
	}
	/**
	 * Sets the outliner's context menu ID.
	 * 
	 * @param menuId the menu ID 
	 */
	protected void setOutlinerContextMenuId(String menuId) {
		fOutlinerContextMenuId= menuId;
	}
			
	/**
	 * Returns the standard action group of this editor.
	 * 
	 * @return returns this editor's standard action group 
	 */
	protected ActionGroup getActionGroup() {
		return fActionGroups;
	} 
	
	/*
	 * @see AbstractTextEditor#editorContextMenuAboutToShow
	 */
	public void editorContextMenuAboutToShow(IMenuManager menu) {