Replying to [comment:1 tj.vantoll]:
Could you include a test case that shows the behavior before that worked (with the older version of the library)? In my testing I always get a small shift: http://jsbin.com/nohovilu/3/edit.
I was previously using jQueryUI v1.8.17 with jQuery 1.7.1, and I've adjusted the example to show the difference in behaviour using these versions compared to jQuery 2.1 and UI 1.10.4: http://jsbin.com/nohovilu/5/edit
Looks like with the former, the width doesn't change upon dragging, though some table rows seem to be shifted down a bit (didn't see this vertical shift in my own application, but perhaps I managed to work around this some other way using CSS and/or JS. Anyway, this is probably not relevant as it seems fixed in the newer version).