Installing MDL results in vertically expanded UI at times
I outlined the bug in a forum post: https://musescore.org/en/node/305114
I haven't seen anything on the issue tracker about this particular bug, so I'll just make a new one:
1) Start playback of score
2) Save score with CTRL+S while it is playing
3) Pause playback
On saving and on pausing the UI's toolbars get thicker. Font size doesn't change. Again, see the forum post.
Uninstall Musescore Drumline, restart.