I don't know if this has been raised before or if the folder images on the left of the main page are supposed to do this but I clicked on the folder image to the left of "C#" and the folder turned grey but didn't take me to the C# section.

Those folder icons tell you the read status of the forum. When you click on the folder, it makes the forum as read, it's not supposed to navigate you to that forum. If you want to go to the forum, click on the name of it instead of the folder beside it.