HTML Form Controls Rendered as if they are disabled in QT5 with Windows Vista application Style

In QT5, when Windows vista application style is used, basically all the html controls (text inputs, text areas, check boxes, radio buttons, drop down selects, etc) are rendered as if they are in a disabled state. You can easily check it with the example pages from http://www.w3schools.com/html/html_examples.asp .

If I use Windows XP application style, there is another bug. The text boxes are rendered with a bluish background color.