Zoran,
Ok, if that's not the simple simple error...
Do you have code in the Paint() and/or Activate() methods anywhere in your class hierarchy?
I don't see the same behavior here at all. Can you run another test? Get the treeview101 sample code from my website, run that form and see if it exhibits the same problem.
>The LockScreen property is .F., and funny thing is that problem goes away if I minimize then restore the VFP window, or if I resize the screen .