OOPS! Can't Undo Deleted Objects

[H Baric]

My mouse cursor wasn't where it was supposed to be (the search field in the dictionary), but on a button which I was in the middle of writing a script for, and I hit the delete key. 

The script editor has sprung a "close or copy & close" on me, so I copied and closed. My UNDO won't play, and I can't get the object back.

Sure, I can redo the object and paste in the script again. But why is it that I can't get objects back when I accidently delete them? I had to ask, because I lost a whole group earlier (AHHHH NOOO) and when it was clear they weren't returning from the grave, I just abandoned it all with the mega grrrrr's.

?

Cheers,
Heather