Fixed the overflow bug in IE7, as per ticket #7004.
BUGFIX: #7004 Fixes
That's artificially limiting the tree width to 200px - what if we make the sidebar user-resizeable? There shouldn't be any width assumptions encoded in the tree. Can't we do this through consistent use of display: inline-block/inline and whitespace: nowrap? Maybe have a look on the jstree.com mailinglist to see if anybody had a similar problem with the tree lib in general?
I can't seem to get IE7 to render whitespace:no-wrap, and it doesn't think you can float objects that don't have widths. I've tried a few different combinations, but they all seem to rely on giving an object a width.
OK, I actually didn't notice the fix was just for IE7 in my initial comments. Its still not great, but an acceptable solution - Thanks Naomi :)