stylesheet_test.py

import sys
from PySide2 import QtWidgets

args = sys.argv
app = QtWidgets.QApplication(args)

w = QtWidgets.QComboBox()
for i in range(10):
    w.addItem(str(i))

style_content = "QWidget:item:selected{background-color: red;}"
w.setStyleSheet(style_content)

w.show()
sys.exit(app.exec_())

why does the stytlesheet entry create an indented combobox item with tick mark on hover?