QAbstractView scroll arrow background color stylesheet?

[evankirkiles]

I have a QComboBox with a large range of options. For some reason, this combobox appears differently in two places despite having the exact same QStringList from which the choices come. While one appears with all the options, one only shows some of them and also displays these very ugly scroll arrows on the sides of the QAbstractView. I
m wondering if I can change the color of these, or even better, remove them for free scrolling. I honestly doubt that I can change their appearance through the stylesheet because they seem to be linked to the MacOS system (when I go into Mojave dark mode, the bright white background turns darker grey). Thus, is there any way to disable the scroll arrows on a QAbstractView in a similar way to disabling scroll bars in a QScrollView? Screenshots: (1st is desired appearance, 2nd is ugly one, both in same application but different windows).