GNOME Developers Hate the Mouse, Remove Middle-Click Paste 13 years ago
This issue has got blown out of proportion, and the facts have been totally lost.
Nothing has been changed. Those of us in the GNOME project were working towards a slightly different solution, which would allow middle-click paste like functionality. That solution didn't work out for the next release (3.10), so we reinstated the old behaviour.
Everyone needs to calm down. We're not going to simply remove middle-click paste.