Disappearing key signature in all but first stave
Score has been written in Eb (3 flats), and this key signature displays in every stave. After a "save", all key signature displays (after the first instance) disappear, leaving second and all following lines showing as the default key of C (although the actual notes are not changed at all.
When Key Eb is then selected from the list and placed over the original (Eb) key signature, all following staves respond by appearing. However, if "save" is then activated, key signatures after the first line are again deleted from view.