If you don't need any values from EventData, use
btnAdd_Action insted of
btnAdd_MouseClicked (EventData As MouseEvent).
Or you can do it that way:
Define a routine with the code, and call it from MouseClicked or from the menu.
Sub btnAdd_MouseClicked (EventData As MouseEvent)
MyRoutine
End Sub
'
'
Sub MyRoutine
'your code
End Sub
Otherwise you would need to define a MouseEvent object with JavaObject to satisfy the signature of the MouseClicked event routine.