Note, this removes the tooltip. It's not super easy to get the cell that the mouse is over, plus all it showed was the Name, which is pretty redundant.
It also removes the popup menu, for the same reason, as it just duplicates the response buttons, and on a ColumnView, right-clicking does not select the hovered row anyway.

Fetched room list for conference.pidgin.im, clicked on the rows, and saw that the buttons were enabled (though I think all responses were chats so they were always enabled once one was selected.) Typed some bit of the names and they were filtered.