Some text editors use Ctrl + H while others Ctrl + R -- some even know both. Should maybe the Find dialog double as Replace dialog, so Ctrl + F would be another option?
Is there user experience style guide on that? Cheers
Gnome recommends Ctrl + H.
KDE recommends Ctrl + R :-(
See also Wikipedia.
Therefore, it is a bug for any non-KDE app to use something other than Ctrl + H for Replace, except when Replace is not separate than Find.