Can't create Custom Theme

[Nefalox]

When I try to create a Custom Theme this is what I get logged in the Console:

Invalid generated unique path '' (input path 'Assets/Scenes/random platforming scene/Assets/Extensions/SuperEditor/EditorResources/Themes/Theme.asset')
UnityEditor.ProjectWindowUtil:CreateAsset (UnityEngine.Object,string)
CGHBNFMMNFMFJNOPDHLEBKJFABAGBPBNAALK.LBBGPIDBLEGLKGGBIIFGOBJNOJGIILIIEFMM:NewTheme ()
UnityEditor.GenericMenu:CatchMenu (object,string[],int)

Is this a Bug or is it a Pro only Feature?

[UnitySuperEditor]

There is a folder called 'Assets' in your project. Try changing the folder name to see if there are any problems

[Nefalox]

The 'Assets' folder is just where all the Project assets are all stored in, I can't rename it or anything since it's setted up by Unity

[Nefalox]

Oops