A key signature changing fails after undo-redo
GIT commit: 073fcdc / Windows7
1) "My First Score"
2) Add a key signature with 2 flats in the first measure (rather by drag and drop, if not, by double-clicking, another reported issue appears : the measure remains hightlighted)
3) Add a C/Am key signature (so, without flats and sharps) in measure 6, ie the second of the second system.
4) Undo twice
First unexpected result: no more key sig in the first measure
5) Redo twice
Other unexpected result: four flats in measure 5