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Hello Duncanmajor, does this issue also occur on v11.5.1? Thank you for asking. I had some issues installing 11.5.1, however the issue did disappear on its own with 11.5. It cropped up again today, but I was able to solve it by simply copying a piece of text from Textedit. Maybe that reboots the cl...

I am having the same issue as well, on Mojave + Cintiq 16.