LibO on Windows XP.
The Help for 'Find & Replace' states that the key combination to access the command is Ctrl+F. In fact it is Ctrl+Alt+F. (Ctrl+F brings up a bar at the foot of the window, whose behaviour is different to the 'Find & Replace' dialog.)
I fixed this on master (-> LibreOffice 3.6), thanks for reporting.
Andras Timar committed a patch related to this issue.
It has been pushed to "feature/gbuild_help":
Command key changed for File & Replace dialog fdo#44396
I added Fix submitter as assignee because this will ease queries and bug tracking.