How can I use the button_Dwon function in the app designer for a text field?

I was used to use the GUIDE and normally I can programm a button Down callback for a text field.

I am trying to do the same for App designer but there is a limitation. I can only use the value_changed or value_changing callbacks.

I was thinking about designing an invisible button onthe text field to have this properity but is it not too stupid?

I would be habby for answers and suggestions