QComboBox style for choosen item in drop-down list

Ok after lot of struggle I made some workaround.. its not best, its not proper, but it looks ok..

I added the bold effect in this way (it affect other widgets like checkable menu items, but I can live with that):

QWidget:item:selected
{
     border: 0px solid #999900;
     background: transparent;
}
QWidget:item:checked
{
     font-weight: bold;
}

Then when I am adding items I am prepending spaces into their text in order to shift it to the right.. I was trying so many things, but nothing affected the QAbstractItemView inside.

This is the result:

I had success with less specific stylesheet selectors and "padding-left":

QComboBox:item {
    padding-left: 20px;  /* move text right to make room for tick mark */
}
QComboBox:item:selected {
    padding-left: 20px;  /* move text right to make room for tick mark */
    border: 2px solid black;
}
QComboBox:item:checked {
    padding-left: 20px;  /* move text right to make room for tick mark */
    font-weight: bold;
}

(probably some unnecessary duplication in that, too!)

I know it's really late, but for people having the same problem: I found this at another question here: Not able to hide Choice-Indicator of the QComboBox

This should hide the indicator/tick:

QComboBox::indicator{
    background-color:transparent;
    selection-background-color:transparent;
    color:transparent;
    selection-color:transparent;
}