QML application window never appears while debugging with QTCreator

I`m trying to create simple QML application. I have QtSDK installed with latest QtCreator. So, i create new Qt Quick application. It launches well and shows "Hello开发者_Go百科 word" text. Then i tried to make some changes and run it again, it stops at "setting breakpoints..." stage, and QML window never appears.

Solved. I had to specify Item width and height attributes, or some anchors to enable qml to determine window size. It is mandatory for main qml window.