When a screen glitches, it is often due to a logic error in the touch screen controller or a temporary short caused by static electricity. The diagnostic tool sends a reset signal or a pattern refresh command to the panel. If the damage is purely logical (not physical), the tool "fixes" it by forcing a hard recalibration of the digitizer and the AMOLED matrix.
The Tool Fixer in action: The phone will cycle through primary colors (Red, Green, Blue, White, Black). Here is the fix: If you see a stuck pixel during the red screen, the tool is not just showing you the problem; it is rapidly cycling voltage through that pixel group. Often, this rapid cycling "unsticks" the liquid crystals in the AMOLED panel. galaxy diagnostics screen tool fixer
You cannot fix a problem without knowing the cause. Here are the top 5 reasons your Galaxy is trapped in diagnostics: When a screen glitches, it is often due