Red Incompatibility triangles are not showing

I’ve been fixing compatibility between 2 masters today (so I know it was working before), and suddenly I don’t see the red triangles on the glyphs. Is this something I could have accidentally toggled off?

Compatibility is only checked for if there is an instance between them that requires Masters to be compatible in the first place. If you want to check compatibility between masters that do not have instances between them, you can use the “enforce compatibility” custom parameter in File > Font Info > Font.

I see the triangles again, but I’m not sure what made the difference. I’ve been working with a single instance the whole time, so I deleted it. I added “enforce compatibility” and no triangles. I created new instances that would fall in between my 2 masters. No triangles. I created instances that matched the 2 masters, so I had a total of 4—still no triangles. I was messing with the “Axes coordinates” weight on an instance and noticed the red triangles. I don’t know if that did it. To test it, I deleted that instance, expecting the triangles to go away. They didn’t. I deleted another instance that was in between the masters. The triangles stayed. I have 2 instances now—both matching the masters and the red triangles are still there. I had those same master instances there before and the red triangles were gone. I don’t understand how it works, but at this point I can continue my work.

If you have Enforce Compatibility, the instances don’t matter. Maybe the view didn’t update right away. Resisting the window probably would have done it.

That is probably it. I will do more experiments. Thanks for the suggestions.