Enhancement: Disable controls in left panel when 0 selected files

[ohrenkino]

see here:

Disable text boxes when no mp3 is selected

I would like to see a feature that if no mp3 is selected in the program, all the tag editing text boxes are disabled or grayed out... there has been several cases where I thought an mp3 was selected and/or somehow got unselected during my typing and the save option is grayed out because nothing is selected... hence wasting time typing the information in when it's useless because nothing was selected and when I select an mp3, the boxes erase themselves... I think disabling or graying out the inpu…