Thanks for the score example. If different staves can have different timesig, we have to deal with it. I tried to sow them, but there a bugs with timeSig. Most of the time "currentStaff->timeSig(_currentMeasureTick);"   only return 0.

If not, draw

Btw, if each staff can have a different time signature, why is the current measure also containing the timeSig?