And since the view has no idea about the buttons, you need to set the backgroundRole for the button's palette to the alternate color manually when you insert the buttons into the cell. Alternatively, set the button's autoFillBackground to false and the underlying cell color will be visible. You will need to remove the background color specification from the style sheet, because the style sheet overrides this setting.

You could also try playing around with the button opacity, but this will probably affect the foreground text as well as the background fill.