Bug: Key signature lost when previous system with section break is deleted
1) New score
2) Create a system with random key-signature, and finish it with a section break.
3) The next system is of the same key-signature as the first as to be expected.
4) Work in that second system (add some notes), relying on that key signature.
5) Now select all of the first system and delete not just the content but the actual measures.
Result: The second system becomes key-less and so all notes that had accidents related to the key signature are now all explicit.
This might take the user by surprise because it looks as if the second section "has" a key signature. When the user deletes the first system, the second system will no longer have that said key signature. It might be argued that this is "by design", but even so, this might want to be reconsidered.
Either the key signature should be reset (no accidentals) after placing a system-break, which I advise against but only very slightly, or the score needs to "re-iterate" internally that there's a key-signature on the next system so that if the previous system is deleted, there's no loss of information and the key-signature remains.
If anyone wanted to test this and is lazy enough to rather download a ready made mscz file with the above steps, included is such a file :)