Thank you very much, this helped me a lot.
Yes you are right, I wanted Button with a sprite and text, I didn't think about scribbles inline sprites, that was exactly the hint I needed. Now it looks like I wanted it:
Now I can continiue prototyping before I begin to tackle the next UI challenges like scrolling and Tooltips.
I already took a look at your scrolling example you posted in the comments, I am excited to see if I can make a working scrollbar, too.