TextField.setEditable(false) should not only prevent people from typing, but it should also prevent the prompt to hide when being focused: It is a bit nasty that the control's SENSE cannot get grasped anymore just because one clicked on the NON-EDITABLE (!) field.

A proposal could be that the prompt goes away only in case TEXT is non-empty instead of hiding it when being focused. That way, the prompt would stay until someone really started to type.