Facebook's input fields don't accept arrow keys
I recently switched back from Safari to Firefox 3.6.4 on OS X 10.6. When typing into the Facebook "What's on your mind?" status field, neither the standard Cocoa begin/end keys (command-left, command-right) nor the Windows-style keys (home/end) have any effect. Oddly, command-shift-left and command-shift-right (select to beginning/end) work, as do Cocoa's emacs bindings (control-a, control-e).
URL of affected sites
I have the same problem even with GMail...
Apple has the proprietary rights for many stupid patents. One of them is the up/down arrows functioning as Home/End in input fields. If I understand correctly, your confusing is because Firefox doesn't have that "technology". It doesn't, and I'm not sure it can for legal reasons... But there may be some extension that implements this behavior. Search for one at addons.mozilla.org.
This is something that Facebook is doing intentionally, I'm not sure why. Maybe because ⌘← is the same as page back?
You can use the up arrow for home (if you're on the top line) and the down arrow for end (if you're on the bottom line.)
You'll notice if you use the search box on Facebook it behaves normally, it's just the status box that's weird.
And morbus, I'd love to see a link to that patent...