I should probably mention that i'm writing this in PyQt5 and therefor tried not to mention the code too much. Since the first thing you mention is the code, does that mean that you think architecturally it should work fine with a standardItemModel? I can always code my way around the crash, but i'm more interested in good architecture for this problem. Do you need more information about the data? Thanks for the reply :)

@kshegunov One might actually need the signal to tell us which flags have changed. Only certain flag changes affect anything we are interested in, several seem not relevant.

You can check you model implementation with the QAbstractItemModelTester. See this wiki entry.

I'm sorry but I don't think will compile. Please provide a minimal, compilable example which shows your problem. E.g int main (int argc, char **argv) { QApplication app(argc, argv); QTreeWidget treeWidget; QTreeWidgetItem *cities = new QTreeWidgetItem(&treeWidget); cities->setText(0, "Cities"); treeWidget.show(); return app.exec(); } See http://doc.qt.io/qt-5/qtreewidgetitem.html#details

@Athius Sure it works, here my code for a bookmark tree: bool dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent) { Q_UNUSED(column) if(action EQ Qt::IgnoreAction) return false; if(action EQ Qt::MoveAction) { QByteArray bytes=data->data(MIME_Bookmark); QDataStream stream(&bytes,QIODevice::QIODevice::ReadOnly); qintptr i; int r,c; stream>>i>>r>>c; QModelIndex index=createIndex(r,c,i); moveRow(index,index.row(),parent,row); } return true; } Of course you need to create and return your custom data in mimeData () as well.

@SGaist Thanks for your advise, it works like well now.