When pinentry-gnome3 asks for a password (with no-grab), I can't use Ctrl-V to
paste the password into the text entry box. I can't even right-click on my
password manager's entry to get it to display the password so that I can
manually type it in.
If I switch to pinentry-gtk-2 (with no-grab) then I can interact with my
password manager but can't paste using Ctrl-V.
If I switch to pinentry-qt4 (with no-grab) then everything works as expected.
The gnome3 problem is due to libgcr, which disables and manages the dialog.
I'll take a look at the gtk2 issue soon. Does pasting with the middle mouse
button work?
Yes, pasting into pinentry-gtk-2 with the middle mouse button does work.
I noticed that pinentry-gnome3 uses GcrSystemPrompt, which is documented as
being a system modal prompt. I'm not very familiar with libgcr, but maybe
pinentry-gnome3 could use GcrPromptDialog if no-grab is set.
I tested this with Fedora 26 and the Gnome 3 desktop. and could not reproduce this. So maybe it got fixed upstream.