The way I get around that is by opening multiple workspaces so I can alt-backtick between them. At least on my setup the ideavim copy buffers are shared between workspaces so I can easily yank from one and paste in the other.
It requires a bit of memory though as IJ just works better if you give it a lot of memory. Not really a problem for me as my dev machines have at least 32 or 64G and besides IJ, firefox and a terminal I don't have much open.