I'm going to write a Wiki article on Timedeltas soon, because it's important. DON'T fix the framerate - please! Games look so much nicer when they're V-Synced and all horrible and teary when you use fixed. This does mean you have to use Timedeltas though, because everyone's display rate is different, so your game runs at different tickrates.
'FPS in caption' is a quick way to see your tickrate, and switch framerate mode to Unlimited for bulletproof timedelta testing. If you move over the whole layout instantly when you just gently tap a control, you probably need to use timedeltas (unlimited should work the same as vsynced if your timedeltas work).