Thanks manios for testing
Klaus it works fine for me, but I've got a last problem, and I'm not sure if it's easy to solve or I oversee something.
My problem is, that my label should have a backgroundimage. When i gave fixed size to my label i used gravity.fill for it, but now with the autosizing the label is as big as the backgroundimage in it's original size.
My first idea was to create two labels, the first one with the text only, autosize it, then read the size of it, and then create a second one, in the background from the first label, use the size of the front label and then use the image with gravity.fill
But i'm sure that this is not the easiest way to solve this. Maybe someone of you have a better idea?