A CustomViewAction is a MenuAction that contains a View instead of an icon or text. This enables embedding of interactive components to a Menu or ToolBar.
Create a new CustomViewAction
A Function to execute when this item is selected.
NOTE: In some cases, the View that the CustomViewAction contains will absorb mouse clicks, making it difficult to select this menu item (and thus trigger the action).
Set the View that is attached to this CustomViewAction.