Thanks Assocracer. Turns out that's exactly the case. I'm fairly new at this and have only ever used regular datum planes. However thanks to your reply I discovered I can go to the properties for the datum plane and change the type. The ones that wouldn't turn off were indeed -A- and...
I have a part where a couple of the datum planes don't turn off when I click the plane display button off (Wildfire 4). I think the person who created the part may have set it up to do this on purpose, but I can't find any setting that let's me control this. Not a big deal, as I can hide the...