The GtkStyle's GTK_STATE_ACTIVE background color can match background color of GTK_STATE_NORMAL, when there is not visible selected days in the calendar, thus fallback to GTK_STATE_SELECTED colors in that case.
The GtkStyle's GTK_STATE_ACTIVE background color can match background color of GTK_STATE_NORMAL, when there is not visible selected days in the calendar, thus fallback to GTK_STATE_SELECTED colors in that case.