Lyrics entry with multimeasure rest selected
1) Press M to enable multimeasure rests in the default "Untitled" score.
2) Click on the multimeasure rest.
3) Press Ctrl+L (macOS: Cmd+L) to enter lyrics.
Expected result: action prevented, with alert that a note or rest needs to be selected.
Actual result: weird, bad stuff. A text field appears far away in the corner of the page; you can type, but only the cursor moves without showing any of the letters; everything disappears when you leave text editing mode.
Problem arises because lyrics entry is supposed to be enabled for normal rests, and currently multimeasure rests are the same type. Fixed as a side effect of https://github.com/musescore/MuseScore/pull/6108/.