I want the child widget to just appear in the center of the parent widget with a horizontal pink stripe. But the widget of the parent becomes very small from PySide6 import QtWidgets, QtGui import sys class WidgetA(QtWidgets.QWidget): def __init__(self): super(WidgetA, self).__init__() self.wb = WidgetB() vbox = QtWidgets.QVBoxLayout() hbox = QtWidgets.QHBoxLayout() hbox.addWidget(self.wb) vbox.addLayout(hbox) self.setLayout(vbox) class WidgetB(QtWidgets.QWidget): def __init__(self): super(WidgetB, self).__init__() palette = self.palette() palette.setColor(QtGui.QPalette.Window, QtGui.QColor("#ff00ff")) self.setPalette(palette) app = QtWidgets.QApplication() window = WidgetA() window.show() sys.exit(app.exec()) If I have not written something, or something is not clear in my question, then ask, I will supplement it source https://stackoverflow.com/questions/70825736/how-...