Hide _thumbs directory

The _thumbs directory appears because probably you have defined the path to the thumbnails directory that points somewhere inside of one of the resource types.
So when that resource type is selected, the _thumbs directory that is inside of it, is being shown.
Change the location of the thumbnails directory in the config file and everything should be ok.

Good news: it will be possible to hide specific folders in the next release.

Another good news: CKFinder 1.2 released.
It means that now you can hide files and folders

Since it's an obvious requirement to hide the thumbnail directory, resulting in everyone having to specify the name twice, could there not just be an option $hideThumbnailDirectory (defaulting to true) in the settings? If set, this would then just add the thumbnail directory to the list automatically.