How to debug why a certain mouse gesture is not working?

I configured a mouse gesture called "up" with a straight line. Once, this gesture worked like all my other gestures with straight lines, but until recently it doesn't any longer. I deleted the action and added it again, even providing a lot of gesture variations and playing around with the recognition drawer, alas without luck.
Are there any ideas what I can try?

Another question on this topic: Is it possible to delete all stored gestures? Maybe by deleting certain files? I suspect that some of my gestures interfere.

Maybe check similar topics/replies for straight lines, e.g. - Straight line gestures - #13 by Andreas_Hegenberg ?