I imported feeds from another site, and organized them using the Organize Sites feature. I have over a hundred feeds, and none of them are displaying the the left sidebar.
As an aside, your Organize Sites feature was breaking. After every move, I could not move again, and had to refresh the page to fix it.
A picture of the issue:
Games/Netsec/Webdev are all expanded on the left, and have no items, even though they’re shown in the Organize Sites modal.
Mac OS 10.10.4, Chrome 47.0.2526.111 64-bit.