12-11-2020, 12:55 AM
The magenta triangle appears in 'LCh mode' (Gimp´s new default--inescapable) to show 'color out of gamut'--maybe very important for some, but I always disregard it.
Look at the top right of your last image: clicking HSV instead makes the triangles disappear.
Look at the top right of your last image: clicking HSV instead makes the triangles disappear.