I have a Problem with my selection box. As you can see (on the screenshot) when I click on my box the possible selctions (the list) doesn't appear above the box. The list instead appears very very far above.
That's the thing, you can't (or it will be a real hassle). And this is because the style for this element is set specifically on this element when you click on the filter. And this styling will overwrite all css classes.
So this is probably something Qlik has to change in their code to be able to make this work.