This has been doing my head in. I hate the mouse for regular tasks.
So the answer to this question is that it's the ENTER key that closes the iCal Event Edit window and preserves your changes. That's the Enter key that's at the bottom right hand corner of a full size keyboard WITH A NUMERIC KEYPAD. The one just above the right hand shift key is actually the RETURN key.
Seems you can make the return key act like the enter key by using Fn with it.
I couldn't see any options in Prefs to make Return equal Enter without Fn.
Now, while I'm here I'm going to see if there's a difference between a full size keyboard, and a laptop. Hold on folks.....
Nope. In order to make the return key on a macbook behave like the enter key on a full size keyboard, you need to use the Fn key with it (which actually on a macbook is a comfortable combination).
Now then, I'm just going to C&P this answer into all the various threads, so if parts of this anwer seem a bit OT bear with me.
What I do think is that some people might be confusing 'editing' an event in iCal with just changing the name of the event. If you click on an event's name (or hit return, or enter), the text goes into edit mode. So you can change it from 'Romantic Night Out With The Wife' to 'Sordid Weekend At Motel With Mistress'. Er, for instance. I'll just try that. Editing, that is, not the Sordid Weekend stuff....
Yup, and then press Enter or Return and the edit is saved. But that's just the title. That's without editing any of the other details (name of motel, length of time you think you can last etc.).
Because what other people (most?) are actually talking about is Doing Cmd+E to edit all the details. If you do that, to alter the venue from 'Mario's Candlelit Bistro' to 'Greasy Joe's Cheap and Cheerful Motel, no questions asked' then you DO need to hit the 'real' ENTER key to save the changes. That's the one on the number pad. Or FN + Return.