At first, thank you Ceylo for all your feedback, it's very appreciated!
Last night I've updated the source code to be compatible with the latest SFML revision, again (thus supporting the modified (and very nice!) sf::Rects).
It might be true that the MSVC and C::B project files are still kinda outdated. Since I'm on Linux and a console kid (
), I'm not maintaining these. I'll ask the proper persons if they can update the project files.
Regarding loading UIs from YAML:
Yes, it's kinda restrictive at the moment, and I'm planning to change the design of code here and there a bit, so that implementing custom widgets is easier. The current implementation needs to have a custom sfg::GUI, which isn't a real problem -- but I agree with you that it's not the way that it's supposed to be.
One idea is to register widget factories with sfg::GUI, that get called after each other when loading YAML files. This way you can extend sfg::GUI with your widgets a lot easier.
Regarding to the GUI designer:
No, there isn't one yet. I also thought about this, but I think I'll better concentrate on the library itself. Maybe another developer will find the time and motivation to create such a tool. If so, I'd really love to see it in action.
Anyways, thanks for your words!