I'm away from my computer at the moment so I can't try to reproduce all your tests, but I did try to use copy-to-vm from Nautilus on a fedora-26 template-based vm and it didn't seem to do anything. The menu just closed.
I can't say if anything else in the Nautilus instance worked after that, as I closed the window after that. -- You received this message because you are subscribed to the Google Groups "qubes-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-devel+unsubscr...@googlegroups.com. To post to this group, send email to qubes-devel@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-devel/5df13ab4-d7cb-42a5-99e5-33e16127df1e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.