Tempo Change Horizontal Lines
It would be great if MuseScore could allow for the drawing of tempo change lines. 'Accel.' can be written, but there's not automatically a line from it, to show the point at which the 'accel.' (etc.) ends.
To the Tempo Change section of the Palette, it could be good to see the items below offered, so users can add a tempo change indication and then drag and let go of the right-hand end of the dotted tail to show where the accel. /rall. /rit. end. Viz: