Local Time Signatures behave like global Time Signatures.

There are a few issues with local Time Signature where they seems to act as a global Time Signature.

To reproduce issue 1):
1) Load Local_TimeSig.mscz
2) Create a local 6/8 TimeSig at the top staff in measure 2 (replacing the 3/4).

Expected behavior: A local 6/8 TimeSig in measure 2 of staff 1 and the global 3/4 TimeSig in the other 2 staves.
Observed behavior: All staves will have a 6/8 TimeSig.

To reproduce issue 2):
1) Load Local_TimeSig.mscz
2) Create a local 6/8 TimeSig in measure 3 of stave 1.
3) Create a local 6/8 TimeSig in measure 3 of stave 3.
4) Select the local TimeSig in stave 3.
Expected behavior: The local TimeSig in stave 3 is deleted.
Observed behavior: Local TimeSig's in both stave 1 and 3 are deleted.

To reproduce issue 3):
1) Load Local_TimeSig.mscz
2) Create a local 6/8 TimeSig in measure 3 of stave 2 (or any other stave).
3) Delete the global 3/4 in measure 2.
Expected behavior: Only a local 6/8 TimeSig in stave 1 of measure 3.
Observed behavior: A local 6/8 TimeSig in stave 1 of measure and a 4/4 TimeSig in stave 2 and 3 of measure 3.

4) Delete one of the local 3/8 TimeSig (in stave 1 or 3).
Expected behavior: The selected TimeSig is removed.
Observed behavior: All TimeSig's in measure 3 are removed.