Copying music between voices

I’m notating a piece for cello and keyboard and Dorico [logically] puts the left hand kb part in a different voice. Unfortunately, this seems to make it impossible to copy music from the piano LH into the cello part. For some reason, the other way around does work: I can copy music I’ve entered in the cello part into the LH of the piano. Does anyone understand the logic of this?

Does this help?

Thanks. I’d figured out one of the workarounds but I’m glad this is going to be addressed soon.