UX improvement: prevent users from accidentally wiping out a song from existing schedule

Currently when going to "Edit" a song, it is too easy to wipe the song out of the current service playlist. And there's no easy way to get it back.

It can be done by either:

1. Clicking "Change song"
2. Clicking Foreground > Lyrics

Unfortunately there is warning or undo button for this. If the user was not paying close attention to the exact name of the song, it can be very difficult to reselect it. If this happens during a service, it can be very frustrating. I've done it myself once or twice.

I would recommend some small UI changes to prevent this:

1. Rename the button from "Change song" (which is confusingly similar to "Edit song") to something like "Select different song..." and perhaps don't colour it green which encourages clicking it. Maybe it should be a warning color like red or orange.

2. Perhaps clicking the "Foreground > Lyrics" tab should NOT wipe out the currently selected song.

3. Perhaps a confirmation dialog box should appear when doing this, asking if the user really does want to remove this song from the schedule and select a different one.

Just some feedback.