How to create a new folder?

How to create a new folder?
I know it is a dumb question but if you have a lot of semgnetaions, there will be no space left where to click to create new folder…

In order to create the folder i have to click on the blank space without any segmentaitons.

Yes, indeed there may be very little or no empty space if there lots of nodes in the scene. You may collapse branches and scroll to see some empty space but it can be indeed challenging. Could you please file a bug report at http://issues.slicer.org/? Thank you.