Quote Originally Posted by jacek
It should should find that plugin all by itself, but if QStyleFactory doesn't know it, then Qt Designer won't know it either. Write a short program that creates QApplication instance and checks QStyleFactory::keys().

What did you pass as the first parameter of the Q_EXPORT_PLUGIN2() macro? Did you compile your plugin in release mode? What is the name of the file with that plugin?
it was compiled in debug mode, now it works, thank you.

I have another problem: when I use preview from the designer it doesn´t call the polish functions. since I implemented only those functions (just wanted to change colors and fonts) nothing changes in the previewed window.