popupmenu call to check active item used by popmenucontroler when dialog propery !=null should be overridden by subclasses
popupmenu call for menu action used by popmenucontroler when dialog propery!=null should be overridden by subclasses
genaral call back to dispatch events back to the dialog...
can be null
Modal dialog with a single textarea to view/edit the JSON user_data of a page element (or a page). Parses the text back to an object on OK and stores it in user_data, wrapped in an undo/redo step.