I am trying to print two parts on the same plate. One needs some supports, the other doesn't need any. When I add the supports in, it adds them to both parts. So I remove all the supports that are not needed and leave the ones I want. When I go to prepare for printing, the supports that I removed on the one part that doesn't need them are added back in. The supports I removed from the other part stay gone. When preparing for printing, it doesn't matter what combination I have the parts selected, they always come back on the part that doesn't need them.
What am I doing wrong?