PySide2 QTreeWidget拖放项在Mac上消失，Python2.7

Question

I'm having a problem where a simple QTreeWidget drag and drop of items causes another item to disappear from the tree. This is on Mac Monterey 12.4, using Python 2.7 and PySide2. I swear that it had been previously working on a Windows platform, although it's been a while since I've tested that. I am also having problems with any widgets that had been added to the item getting lost when it re-creates the item in it's new place, so bonus points if anyone knows how to prevent that as well and can show a simple example.

(I'm working in Maya, so there is some code for displaying the UI there, and I haven't tested the section that would be more generic for use outside of Maya.)

Thanks so much for any help!...

import sys
from PySide2 import QtCore, QtWidgets


def main():
    try:
        app = QtWidgets.QApplication(sys.argv)
        ui = TreeUI()
        ui.show()
        app.exec_()
    except RuntimeError:
        from maya import OpenMayaUI as omui
        try:
            import shiboken2 as shiboken
        except ImportError:
            import shiboken
        pointer = omui.MQtUtil.mainWindow()
        win = shiboken.wrapInstance(long(pointer), QtWidgets.QWidget)
        ui = TreeUI(parent=win)
        ui.show()


class Tree(QtWidgets.QTreeWidget):
    def __init__(self, parent=None):
        super(Tree, self).__init__(parent)
        self.setHeaderLabels(('name', 'widget'))
        self.setSelectionMode(self.SingleSelection)
        self.setDragEnabled(True)
        self.setDropIndicatorShown(True)
        self.setDragDropMode(self.InternalMove)


class TreeUI(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(TreeUI, self).__init__(parent)
        widget = QtWidgets.QWidget(self)
        self.setCentralWidget(widget)
        tree = Tree()
        for x in range(0, 6):
            item = QtWidgets.QTreeWidgetItem(tree, ('item{}'.format(x), None))
            item.setFlags(item.flags() & ~QtCore.Qt.ItemIsDropEnabled)
            button = QtWidgets.QPushButton('Button{}'.format(x))
            tree.setItemWidget(item, 1, button)
        layout = QtWidgets.QVBoxLayout(widget)
        layout.addWidget(tree)


main()

Answer 1

Ah hah! I got it working, thanks to @musicamante, I was able to get it working. Adding in a custom dropEvent that calls the dropMimeData function, and then accepts the event, seems to fix it up:

class Tree(QtWidgets.QTreeWidget):

    def __init__(self, parent=None):
        super(Tree, self).__init__(parent)
        self.setHeaderLabels(('name', 'widget'))
        self.setSelectionMode(self.SingleSelection)
        self.setDragEnabled(True)
        self.setDropIndicatorShown(True)
        self.setDragDropMode(self.InternalMove)

    def dropEvent(self, event):
        index = self.indexAt(event.pos())
        parent = index.parent()
        self.model().dropMimeData(
            event.mimeData(),
            event.dropAction(),
            index.row(),
            index.column(),
            parent
        )
        event.accept()

It still has the problem of the associated widgets being lost, but I can post that as a separate issue.