no scroll bar after content has been appended

This is a great scrolling plugin! However I have stumbled across a small issue.

Say I am appending content like chat and there isn't quite enough content in the div yet when it reaches the point there is enough content the scroll bar doesn't appear but however the scroll mechanisms are fine! Its just the UI isn't retained.

http://jsfiddle.net/DY9CT/5/

Start by reproducing the behavior in the linked jsfiddle, appending content until the scroll bar should appear. Trace how the plugin updates its scroll-bar UI after content changes; done means the bar becomes visible while scrolling continues to work.

Written by the indexing model from the issue text.