Clean up styles

I've begun the work of making the implementation of style methods more uniform and correct, but this got to be so big that I decided to stop half-way.

This PR will represent "cleaning up" `arc` - `list_box` (using the list in #711).

I'll make lots of inline comments on what I considered "cleaning" and I'm eager to hear feedback.
that doesn't seem good to me. If you call `choose` on the backend the frontend choose method will never be invoked and therefore data won't be stored in the DSL layer/hash which will have implications. Same for items, the GUI will display them but they won't be in the hash. I'm for reverting this change. 

It's the preferred way (imo) to set data on the DSL level and then pass an update event/something along to the backend as the backend shall represent the DSL element.