Scene editor for level designing/GUI?

[Undume]

Is there any kind of editor?
Im not asking for a full editor like in Unity there is. With a buggy and unfinished editor as is cocos studio from cocos2d-x, it would be enough.
It helps us a lot.. im tired of doing relatives positions with pen and paper

[JayhawkZombie]

You can develop your own GUI system, or you can check out the GUI systems already in-place using SFML, like SFGUI http://sfgui.sfml-dev.de/
or TGUI: https://tgui.eu/

I don't know how often they are updated, so I'm making my own GUI system.  But plenty of people have used both SFGUI and TGUI and they're both documented.

I'm not aware of a stand-alone editor already made using SFML.  But if I find one I'll update my post.

[Hapax]

For level designing, you may want to consider Tiled. It's mostly grid-based and useful for a number of applications. It exports to a few common formats too.

[fallahn]

I'll second Tiled - not just for tile maps. I used it in to create navigation nodes and lay out prop / activity positions.