Alternatively, if you don't think the gap between groups is good idea:
It would be great if you could at least use the space that's already there!
<img src="https://dl.dropbox.com/u/1024727/c2/gap.PNG" border="0" />
Currently, right clicking and inserting in a space like that puts it at the bottom of the sheet!
I think it would be fantastic if it would place it closest to where the mouse is!