Staff Text button disappears
Background: Takes a few times to reproduce but I would hardly say it is random as I can always get it to happen. Note I have the Palettes panel visible all the time. I'm writing some rhythms for my daughter just using Treble clef and using "Staff Text" a lot to notate how to count, but often the button disappears after a short while and I have to restart Musescore to make the button appear again.
1) For example create a handful of measures with all Eighth notes.
2) Assign "Staff Text" to each note for counting (e.g. rename notes to "1", "+", "2", "+", "3", "+", "4", "+").
3) Now select the first note in the measure and add another "Staff Text" element. Rename it to "Count me".
If notes are rather close together, this usually causes one or more previously set text values (e.g. "+ 2") to become positioned above the new text "Count me".
4) Now rectify the vertical position of the new "Count me" (which is on the bottom) by selecting it, and then holding UP arrow until it moves a considerable distance up. Note this also pushes the "+ 2" text up with it.
5) Now select "+ 2" and use SHIFT + MOUSE (red dots and lines appear) and drag it down until it arrives at or close to its original position. (sorry, cannot get screenshot of that)
6) Using the same select/shift/mouse method, drag "Count me" down until you get it just above the "1 + 2" text you first added.
It usually takes a handful of times in repeating this procedure, then suddenly in the Palettes panel (I don't know precisely when), the button "Staff Text" will be all white and no longer functional.
O/S: Windows 7