Do not call the HandlesTarget method. This method is called automatically when the user invokes an object (such as a tool button or menu item) that is linked to this action. The HandlesTarget method provides the action object with an opportunity to indicate whether it is appropriate to execute at this time with the object specified by the Target parameter as a “target”. Target is the currently active object. HandlesTarget checks whether the Target is a TCustomEdit or any subclass of TCustomEdit. If the Target is nil (Delphi) or NULL (C++), HandlesTarget checks whether the Control property of this action is a TCustomEdit or any subclass of TCustomEdit. HandlesTarget returns True if there is an edit control to act as target, or False otherwise. 

UpdateTarget