Upload Zone Auto

Fantastic Plugin! Congrats!

One question: 

I have an Background image and an Upload Zone with auto selection. 

If the user uploads an image on the Upload Zone (it is auto selected so the user is in the correct area at the start) everything works fine. Then the user wants to change the image so he deletes the uploaded image.

Unfortunately the selection is lost because of the delete action, so if the user uploads another image - the image is not in the upload zone, but on the background all over the canvas. 

So the question - is there any possibility to lock every layer apart from the upload zone, so that the user has always selected the correct upload zone?

Best regards

Gerald