F3 is usually associated for searching... It's not a good idea to break existing or standard used shortcuts in Windows.
Anyways, yes, maybe it is a good idea for a futur release that a registry tweak is included where you can set your preferred shortcuts. But if and when it is added, be very carefull in assigning anything. Many shortcuts are already been used thruout windows and are standard in many applications (like the CTRL+TAB, CTRL+PGDN for tabbed browsing); it is best that you learn (or don't forget about) to use the standard shortcuts so you don't get into bad habbits (eg: F3/F4 wont work in your browser when you want to switch tabs there)
/ 
