Looks like the whole BREW stuff is missing.

I'm not familiar with the styles engine, so I'd be grateful if someone made selection color customizable(currently hardcoded sf::Color::Blue).

It's quite simple. Just have a look at the existing BREW elements.

Looks like the whole BREW stuff is missing.

The whole BREW rendering seems to be integrated inside the widget itself (in ListBox::invalidateImpl()). I can change @Zax37 code to put the rendering code in the BREW renderer and make another PR if you still wants this widget (I'm interested by this particular one for a project of mine).

Sure, go for it.

Its ListBox implementation doesn't support scrollbars (it keeps growing when items are added). Should I add support for scrollbars (vertical at least) or keep it simple while the user can still have scrollbars by combining it with a ScrolledWindow ?

It would be nice if the user didn't have to do so much work themselves for something they almost always expect. Add the scrollbars... 😉

Ok, will do it :)

I know how to add and manage the vertical scrollbar (scroll item by item) but I don't know how I can manage a horizontal scrollbar. Putting "..." at the end of the item's text if it is too large could be a better (and easier ^^) idea.

Made the implementation in my feature/listbox branch : https://github.com/victorlevasseur/SFGUI/tree/feature/listbox

What do you think of it ? (some features are still missing)

I'm also waiting for this one :)