Since the merging of 2 staves into separate voices in one staff is unavailable in Notion right now, we have to find a workaround. One is to copy staff B in voice 2 of staff A. Fine. But then we can arrive at a situation where the rests of voice 1 are overlapping notes of voice 2. Fine. Lets select all of the rests and move them out of the way a bit so that they dont overlap. Right now the only option if to shift click all of the rests one by one. Very tedious. Another example: you have a 32 measure part and you are still not sure whether you prefer c or c#. Again the only option if to shift click all of them one by one. In my opinion, multiple select of any one item is a must.