I am not from MM, so these comments may not be 100% accurate
Firstly your database should be OK. Runtime info, like your current window settings, your current selections ... things like that ... are stored in a file with a name like persistent.json (I am travelling at the moment, so don't have MM with me)
To reset, you could:
- find that file ... is with your database, in the Portable directory
- rename that file, so the MM5 can't find it
- I am fairly sure that MM5 will just create a clean version of persisternt.json for you
But before you do anything, check whether you have selected multiple tracks ... when you do that, individual track fields like track name, track artist, etc become disabled, because any update that you are going to do will affect
all selected tracks
MM5 track selection is a bit quirky ... You can see which tracks are selected by the tick in the top right corner when you are in grid mode.