Hi,
There is one way you can do this, but it's quite tedious: Notes in a single bar can be selected by clicking on the first note in the bar, then shift-clicking on the last note in the bar. You can then copy and paste these into another bar without overwriting notes on another staff.
Unfortunately the bar-level copy copies all staves of a bar, and so overwrites all staves when pasted. We'll look at how this can be improved in the future.
Alex