strange grids

After changing the background color of my Scapple board (and sometimes also when I move my notes) I get some strange grid lines. How can I prevent the gridlines ? (pageguides are off)

This looks like an old redraw bug that was fixed years ago. So make sure you are using the latest version, and let us know what version of macOS you use.

I use Scapple 1.30.4 (468) and macOS Catalina 10.15.4.
The bug occurred with these latest versions.

Thanks for confirming that. I rebooted to my 10.15 testing volume, and still cannot reproduce these lines. I tried a few different things as you suggested, changing the background colour first, and then moving notes around.

A thing like this might require a few ingredients in order to appear. Do you regularly operate at a non-standard zoom setting? Use Full Screen mode? Separate monitors? What preferences have you changed from the defaults (and does the problem persist if you reset your preferences)? Anything you can think of along those lines might help.

I presume these go away when you restart the software?

The problem appears when I have a lot of notes and I zoom in (and play a bit around with the entries -> moving notes). The problem does not appear without zooming in. The strange grid-lines vanish after pressing z-button. But they immediately appear again if I leave the z-fullscreen-mode and move the notes.

I use standard iMac monitor and already changed to default settings (after resetting any preferences).

Okay, I’ll test with the conditions you’ve described, thanks.