You might try a reset: Press Cmd+Opt+Shift (Mac) or Ctrl+Alt+Shift (Win) immediately after initiating Photoshop startup. Select "yes" when prompted. You must press Cmd+Opt+Shift (Mac) or Ctrl+Alt+Shift (Win) after initiating Photoshop's start up, but before the blue start up screen appears.
i tried that but i am unfortunately getting the same result. any other ideas?
thanks for your quick response.
Not sure what's going there myself. Video-driver-related issue, maybe?
Let's try a Reset on Levels. Open Levels, then press and hold Alt (Windows) or Option (Mac) on your keyboard.
The Cancel button will change to Reset. Click on it, restart Photoshop and try again.