Double click key signature in new score wizard affects current score

Ubuntu 14.04, GIT commit: 6c121cb

This was originally reported as comment #1 in #43301: Implied C major key signature at beginning of score does not transpose, corrupts on create new score.

1) new score, key of D
2) select all
3) ctrl+n to create new score
4) enter info in first screen if desired; next
5) double click Eb key signature

Result: key signature of *current* score changes, starting with second system (with courtesy key signature at end of first). As far as I can tell, everything is actually OK at that point, and an Undo will restore you to where you were, or you can delete the spruious key signature. Except that there is actually a key change registed at *each* system break, so you'll have a whole bunch of them to delete. That is, the key signature that appear at the start of each system after the first are not "generated".