Application Size is huge on dual monitor setup
S3 - Major
Open MuseScore with a dual-monitor setup on Linux and it'll take up everything. You can't try to make it smaller, or if there is a way to, it's too complicated for an average user to figure out.
Use the command line option -d xxx with a suitable DPI value for xxx
I assume this is only actually true if the display DPI values differ between the two monitors, and you start MuseScore on one monitor but are checking the results on the other. That is, it isn't so much that all dual monitor setups automatically cause this, it's really a special case of the DPI mismatch discussed in other issues.