And scrolling won't work when mouse cursor is outside of the UIContainer the UISelect is in.

Ths following code in construct() shows the issue:

        UIBackgroundContainer cont = new UIBackgroundContainer(this);
        cont.setSize(100, 60);

        UISelect<String> select = new UISelect<>(this, 80, Lists.newArrayList("qwertyuiopasdfghjklzxcvbnm".split("")));
        select.maxDisplayedOptions(10);
        select.setSelectedOption("q");
        cont.add(select);
        addToScreen(cont);

Screenshots that show the issue:

You also can't actually select any of the options that are below the container it's in by clicking them.

And I have actually no idea how to fix that.
When you click outside the container, it doesn't cascade the event to the components inside it.

Note that this also affects MalisisDoors (I used it recently and noticed that)

Fixed.