JQuery :: Unable To Display Collapsed Folder Correctly Once Expanded - CSS ?

When the left column first loads the vertical scrollbar displays correctly.

The vertical scrollbar is aligned up against the right border of the first column of the table which you can see by looking at the first image, and comparing it to the second.

Once I click on a folder in order to expand its contents, the vertical scrollbar introduces a gap of about 20 pixels as shown in the circle.

I looked at the css tag for the "classes" folder using firebug, and it showed {class ="directory collapsed", class= "directory expanded"} prior to and after expanding the contents of the folder.

I did a global regex search, within the project hierarchy, for (collapsed|expanded) and could not find any css that showed any margin-right for expanded, nor could I find any css at all related to "directory (collapsed|expanded)".

The only thing I found was that jqueryFileTree.js contained a function bindTree(t) with some code that toggled (collapsed|expanded):

Does anybody have a clue what is causing the gap once I click on a folder, and how to fix the problem?

Even if close the folder once the gap is there, I can't get rid of it unless I reload the page.