Invalid pixels have transparency set to 100% yet they are not black. These pixels are inverting background color if used on cursors. They should not be present in normal images.
1444
Invalid reference
1445
Inverse (small images first)
1446
Invert Y
1447
Invert selection
1448
Invert the direction of vertical rotation when using mouse or keyboard.
1449
Iridium...
1450
It is recommended to save and close all other documents and restart the program.