This idiom alone has kept me using xemacs for over a decade. I'd like
to switch to emacs now.
Can I fix this easily with option-setting, or does it require me to
hack and add the correct behavior?
Simply add a keybinding for that:
--8<---------------cut here---------------start------------->8---
(define-key isearch-mode-map (kbd "<mouse-2>")
'isearch-yank-x-selection)
--8<---------------cut here---------------end--------------->8---
If you don't like how that expands the region (including highlighting),
then use something like that to deactivate the mark before:
--8<---------------cut here---------------start------------->8---
(define-key isearch-mode-map (kbd "<mouse-2>")
(lambda ()
(interactive)
(deactivate-mark)
(isearch-yank-x-selection)))
--8<---------------cut here---------------end--------------->8---