Thanks Paul.
Now I know that it is somekind of a GUI problem, but I don't know what exactly and I'm not able to reproduce it here and checking through the code I still don't see anything.
So, I put the label show and hide code back to the app and changed a few things a bit and added a try/catch block to this particular code with a MessageBox,
so in case the code generates an exception then you will see a Messagebox showing the exception message.
I've uploaded the test exe file to the same link as previously.
The download link
http://www.cncdrive.com/UCCNC/UCCNC.exeJust replace the UCCNC.exe file in your UCCNC installation. Do not rename the file.
Could you please test this and let me know if it freezes the app. or not and if you get any error messages?
And by the way what Operating System you running?