Found the issue with screenshots on #MangoWC having random lines in them.
I have found out that it is caused by animations on the layerrule for slurp. Previously I had as per the docs:

layerrule=noblur:1,layer_name:selection

But have discovered if I also disable animations for slurp then it takes crystal clear screenshot selections now.

layerrule=noanim:1,noblur:1,layer_name:selection

https://mangowc.vercel.app/docs/window-management/rules#layer-rules

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