Change the staff assignment of score symbols
In addition to notes, most other score symbols can be assigned to a particular staff in a multiple-staff staff style. The Event inspector includes a Staff parameter where you can set the staff for these symbols.
Change the staff for a score symbol
Select the symbol in the score.
You might need to use the Layout tool to select the symbol.
In the Event inspector, drag the Staff number up or down to change the staff for the selected symbol.