flickering colors and tools bug

[Ofnuts]

AFAIK, most occurrences of such problems have been found to come from:

• Hardware:
  • Plain defective, such as worn out contacts that "bounce" and send multiple strokes/clicks or stuck keys
    
  • Doing strange things, like for instance that Logitech mouse that appears to the PC as a mouse+keyboard and actually sends keyboard keystrokes
    
• Software that intercepts the flow of events:
  • Session recorders
    
  • Security software
    

Gimp uses mouse/keyboard more intensively than other software so is the first to demonstrate trouble. Usually it's Gimp that tells me that my mouse batteries are dying.

To debug all this, a first thing to do is to spot a repeatable misbehavior, figure out what mouse/keyboard event is supposed to trigger this in Gimp, and then wonder how that event is produced.