Pyqt -在添加到"IconMode“中的QTreeViewItem时，在自定义小部件上丢失选择高亮显示

import sys
from PyQt5.QtWidgets import QApplication, QTreeView, QWidget, QVBoxLayout, QLabel, QStyledItemDelegate, QStyleOptionViewItem
from PyQt5.QtCore import Qt, QModelIndex
from PyQt5.QtGui import QStandardItemModel, QStandardItem

class CustomWidget(QWidget):
    def __init__(self, text):
        super().__init__()
        layout = QVBoxLayout(self)
        label = QLabel(text)
        layout.addWidget(label)

class CustomDelegate(QStyledItemDelegate):
    def createEditor(self, parent, option, index):
        widget = CustomWidget("Custom Item")
        return widget

    def paint(self, painter, option, index):
        if option.state & QStyle.State_Selected:
            painter.fillRect(option.rect, option.palette.highlight())
        super().paint(painter, option, index)

class TreeViewExample(QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.treeView = QTreeView()
        model = QStandardItemModel()
        rootItem = model.invisibleRootItem()

        item1 = QStandardItem("Item 1")
        item2 = QStandardItem("Item 2")
        rootItem.appendRow(item1)
        rootItem.appendRow(item2)

        self.treeView.setModel(model)
        self.treeView.setItemDelegate(CustomDelegate())

        layout = QVBoxLayout()
        layout.addWidget(self.treeView)
        self.setLayout(layout)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = TreeViewExample()
    ex.show()
    sys.exit(app.exec_())