Scanimage not refreshing image during "focus"

I don’t see any Scanimage posts ere, but perhaps there are users?

I am a new user of Scanimage 5.7R1 (so the last free version), running it under Matlab 2020b.

The “Focus” function should show me live image while I move the stage, adjust laser power etc. And it does, but the image freezes… unless I constantly move the coursor over the image. Anyone experienced this? Can it be something that changed in a newer version of Matlab, or a setting in Matlab regarding refresing a figure?