No I did not typed that. I did a right click and added it from the Context Menu. No Idea what went wrong. I fixed it now. Also what confused me for a while: In the C++ Header File I have to write "LabelBase Label1" but in the Layout File it is just Upp::Label - guess that is Part of the Charme of UPP. And here I thought Qt was doing some weird mixed things. Seems UPP is doing even more things to achieve that "Less Lines of Code Concept"