Canvas contents sometimes become invisible
I've tested this on Debian and Windows 10, both 64-bit.
In this patch: "doc/4.data.structures/pd-l2ork/sprite-game/sound.pd" I can open the canvases "plucks" and "baseline" without any problems. However, if I close these canvases, then click the toggle button to start the metro, and then re-open the canvases, their contents seem to disappear.
I think it might have something to do with the message boxes and their values being changed with the "set" method.