MATLAB: How to set a GUI edit text to clear the first time text is entered

Question

I wanted the opening text in my Edit Text button to clear whenever a key was pressed, but never afterwards. I tried to do this using a "FirstEdit" field in handles set to "false" in opening function (after initializing Edit):

 function GUI_OpeningFcn(...)
 % ...
 set(handles.edit1,'String','Initial Text')
 handles.FirstEdit = true;

Then, I would modify edit1's keypress to wipe the text field once only:

 function edit1_KeyPressFcn(...)
 %...
 if handles.FirstEdit == true
     set(handles.edit1,'String','')
     handles.FirstEdit = false;
 end

Unfortunately, the FirstEdit variable resets to its initial (OpeningFcn) value after every button press. What am I not getting? Is there a way to implement this?

Answer 1

Did you remember to store the modified handles struct?

 function edit1_KeyPressFcn(...)
 %...
 if handles.FirstEdit == true
     set(handles.edit1,'String','')
     handles.FirstEdit = false;
 end
 guidata(hObject, handles)
 ...

Otherwise the changes of the struct are lost, when the function is left.