Timeline control rows (time signature etc) no longer hideable

[MarcSabatella]

In the Timeline, it used to be possible (via right-click menu) to hide individual rows in the top pane - the time signature, barlines, etc. Right-click no longer does anything. It was never good to bury this option in the right-click menu anyhow, but an icon to restore those controls would be nice, so you can easily create a more streamlined timeline.

Also, there are visibility toggles for the instrument rows. These used to hide the instrument in the score itself. These controls are present but no longer work. Rather than worry about fixing this, I propose those just be removed, since this functionality is in the instruments panel now.

[DmitryArefiev]

bandicam.2022-04-14.19-21-57-383.mp4

[iainhallam]

Seems like this should be in a menu from a settings icon on the timeline rather than right-clicking, for discoverability, but I agree that this would be useful. In fact, it would be useful to be able to hide the instruments part as well to leave just the landmarks in complex scores.