I’m asking because I’m trying to do this control [img839.imageshack.us] , when I press the combo arrow I want to call QColorDialog, this is easy , the hard part is to create that combo and update its color with the one that I choose from QColorDialog

You could create a pixmap in runtime with letter A underlined with appropriate color and display this pixmap. This solution is likely to be not very fast but maybe it will work.