I have never seen this in any platform, any os, any browser, any web platform where the user must be case sensitive with a Ctrl-F find command. The Opera find command breaks a universal method for finding text.
The user experience is downgraded by having to now remember to search not once, but many times to find text that matches all possible cases on a webpage.
There does not appear to be any user controlled option to change the function of the find function. Please change this.