Inconsistent QListWidget drag&drop behaviour on Win and macOS

[fcona]

What happens if you call only setDragDropMode() and not setDefaultDropAction() or setMovement()

It seems this was enough to get everything working!
That is, to get the behaviour I want I just need to call setDragDropMopde(QAbstractItemView::InternalMove). Any call to setDefaultDropAction() or setMovement() interferes somehow. I got confused cause on Win the call to setDefaultDropAction() does not change the overall behaviour (at least nothing I could notice), while on Mac it breaks the d'n'd, making items disappear whenever they are moved.
I also implemented the further suggested fix (no items vector and calls to QListWidget::item).
Here's for future reference the full mainwindow.cpp that works for me

#include "mainwindow.h"
#include "ui_mainwindow.h"
 
#include <QBoxLayout>
#include <QDebug>
 
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 
    QWidget * w = new QWidget;
    this->setCentralWidget(w);
 
    QVBoxLayout * vl = new QVBoxLayout;
    w->setLayout(vl);
 
    lw = new QListWidget;
    vl->layout()->addWidget(lw);
 
    lw->setDragDropMode(QAbstractItemView::InternalMove);
//    lw->setDefaultDropAction(Qt::MoveAction); REMOVED
//    lw->setMovement(QListView::Snap); REMOVED
 
    lw->addItem(new QListWidgetItem("item 1"));
    lw->addItem(new QListWidgetItem("item 2"));
    lw->addItem(new QListWidgetItem("item 3"));
 
    QAbstractItemModel * model = lw->model();
    connect(model, &QAbstractItemModel::rowsMoved, this, [=] (const QModelIndex &, int from, int, const QModelIndex &, int to)
    {
        qDebug() << "moved item from" << from << "to" << to;
    });
}
 
MainWindow::~MainWindow()
{
    for (int i = 0; i < lw->count(); i++)
    {
        qDebug() << lw->item(i)->text();
    }
    delete ui;
}

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QBoxLayout>
#include <QDebug>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    QWidget * w = new QWidget;
    this->setCentralWidget(w);

    QVBoxLayout * vl = new QVBoxLayout;
    w->setLayout(vl);

    lw = new QListWidget;
    vl->layout()->addWidget(lw);

    lw->setDragDropMode(QAbstractItemView::InternalMove);
//    lw->setDefaultDropAction(Qt::MoveAction); REMOVED
//    lw->setMovement(QListView::Snap); REMOVED

    lw->addItem(new QListWidgetItem("item 1"));
    lw->addItem(new QListWidgetItem("item 2"));
    lw->addItem(new QListWidgetItem("item 3"));

    QAbstractItemModel * model = lw->model();
    connect(model, &QAbstractItemModel::rowsMoved, this, [=] (const QModelIndex &, int from, int, const QModelIndex &, int to)
    {
        qDebug() << "moved item from" << from << "to" << to;
    });
}

MainWindow::~MainWindow()
{
    for (int i = 0; i < lw->count(); i++)
    {
        qDebug() << lw->item(i)->text();
    }
    delete ui;
}

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and of course you need this declaration too in MainWindow's properties:

QListWidget * lw;

QListWidget * lw;

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Thank you very much for your help!