I know that to hide rests in other voices I have to enable the switch in the lower panel where it says Begins Voice or Ends Voice, but this switch doesn’t stick when I try this. Is this A bug?
First you have to make sure it is the right voice you are trying to start/end. To achieve this, in the View menu, Note colours, enable voice colours. You will then see the colour of the voice of the rest you need to get rid of. If the start/end thing does not work, select and delete the rest and then retry start/end.
If this does not work, I suggest you send a picture of the problem (with colours enabled) or a zipped dorico file.
That actually worked, thanks so much, Marc!