2 issues I found:
1: with wordwrapping on, there's times the script gets a little confused when you use the up/down arrow keys, and you'll have the wrapped line superimposed on the unwrapped line that should be 2 spots down.
2: not entirely compatible with jquery dialog. That or I need to work harder on declarations... I found that as long as the jqurey dialog was declared with autoOpen:true, EditArea worked fine; but if AutoOpen was false for the jquery dialog, EditArea failed to display properly and wailed to work.
If I wasn't intent on sticking this into a dialog, I'd be using it (and it's possible I'll go back and redo things)