I have opened many tabs while working on project. (new feature in Xcode 4).
But for switching from one tab to other tab, the only way I\'ve found to do this is to us
If the shortcuts don't work (because of language, for example), you can define custom shortcut:
XCode -> Preferences -> Key bindings
Make sure that "all" is selected
Define shortcuts for "Select Previous Tab" and "Select Next Tab"
I used cmd+pageup and cmd+pagedown, didn't generate any conflicts.