the background color shouldn't have any effect on it, neither border should have any effect. The problem is that i can't see any style sheet property in Qt documentation for specifying an icon for tabs and aligning them. So, the only solution i can think of is custom drawing so you can specify the position (alignment) of the icon yourself.

And as you said when you don't specify a style sheet or don't use background and border properties it shows up fine. So, i guess this is just a Qt bug (default behavior?). One more point: don't use the "align" property in your style sheet, i get this error when i use the align property:

"Unknown property align"