what exactly did you to “make the sysroot field empty”? This might be interesting for other developers having this problem. I’m still wondering why this was not required on my PCs where it worked fine out of the box.
The second question is a bit trickier:
To get the maximum performance on mobile devices, we have implemented a custom version of a cocos2d-x renderer instead of the default Qt renderer. This change allows to render with 60fps and lots of animated sprites, which is not possible with the Qt renderer. This also means, however, that we do not support all properties of Rectangle and Text component in our renderer. The currently not supported properties are exactly the ones you are trying to change! So no italic fonts and no gradients/radius/borders are possible until our next major update of the renderer early 2014! However, from a performance point of view I still discourage to use the Rectangle element in production games, because there rendering is slower than images. The best option you have, is designing any buttons as images where you can make them rounded and with custom gradients, and then render these buttons as images instead of Rectangles.