At least in FF2, that was not the behaviour. I don't remember FF1.5.
Ctrl+F has always, from what I recall, jumped text input to the search
box and highlighted whatever text is already in it.
** Changed in: firefox-3.0 (Ubuntu)
Status: Incomplete = Invalid
--
Pressing CTRL+F the search
** Attachment added: Dependencies.txt
http://launchpadlibrarian.net/14877107/Dependencies.txt
** Attachment added: ExtensionSummary.txt
http://launchpadlibrarian.net/14877108/ExtensionSummary.txt
** Attachment added: profiles.ini.txt