Yes, I need the div...
The sidebar does collapse when it is empty of all content. However, when I have a (div style="display: none:") in sidebar the sidebar won't collapse even though the div is not visible.
I have tried various style attributes such as: style="display: none !important; height: 0px; width: 0px; overflow: hidden; position: absolute; left: -1000px; visibility: collapse;"
The sidebar simply won't collapse with this div inside it.