Xcode 4 Cmd+alt+up/down remapping

I realise that switching between header and implementation files has moved to ctrl+cmd+up/down.

however this is incredibly annoying, as there is no Ctrl button near the arrow keys, before I could do it quickly with 3 fingers on one hand.

So i opened up preferences found that I could change the key binding开发者_如何学JAVAs and attempted to press cmd+alt+up/down. However it seems that it is the only box that refuses to accept the alt key. I tried any combination of alt+any key, and it just entered the key without alt. How can I bypass this? Is there a manual way of setting key bindings, and why on earth is alt not allowed in these 2 particular key bindings?

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I reported a bug at apple. (Problem ID: 9125898)

Please add any details there.. [edit] oops, not possible.. Just submit another one :)

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Not sure if it's a bug but YES you can remap it. However the behavior is a little different from that in Xcode 3. You can set it to Cmd+alt+up /down in Preferences. Note that you can't set the alt key on "Jump to Next Counterpart" but only "Jump to Next Counterpart (option)".

This new key binding will open implementation/interface file in Assistant Editor side-by-side with the original editor.

Cmd+Return to close the Assistant Editor.