I was doing a mask for Ha data. Duplicate, select and inverse. The Mask wasn't showing at all. However, if non-inversed, it was showing as Red. What am I missing ? I restarted several times but with the same result. I looked at colour management set-up but couldn't see anything. I probably clicked on something but don't know how to resolve this. Same with SII and Oiii. It was working the day before.