oops...
I just tried Qt creator 2.0 Alpha,and it crashes a lot. Especially when using the Designer For QML.

One more problem is (though I asked it in another post,but no good answer)
Most programs use PNG file for buttons.And images of hover, normal,pressed states of a button are in just one PNG file.
I wonder if there is a way in Qt style sheet to use a part of a PNG file.
(I really wish there would be a way.....)