Tiny bug really, not a massive show stopper; should be quick fix?!
So I've just opened a saved file and usually when doing anything - adding a note, changing a slider, or collapsing the track for example - the file icon in the top bar becomes faded signifying a change has been made to the file. This does not happen for me when changing a track's mute or solo state.
The only scenario could be that problematic is if you've selected a bunch of tracks to mute or solo-ed and you switch to another song, the save dialog prompt won't appear?