Improve drag-and-drop visual handling in DragWidget

Modified the mousePressEvent in DragWidget to
temporarily detach the dragged QLabel from its
parent using setParent(nullptr). This ensures the
dragged widget remains visible and above other
widgets during the drag operation. Re-parenting
logic was added to restore the QLabel to its o
riginal container if the drag action is not a
MoveAction. This change addresses visual issues
where dragged items could disappear behind
overlapping widgets, enhancing user experience
and maintaining consistent behavior.

Task-number: QTBUG-123777
Pick-to: 6.6.2
Change-Id: I3edce9c96815e32eb8f00b61f7eda1709de04b4d
Reviewed-by: Richard Moe Gustavsen <[email protected]>

examples/widgets/draganddrop/draggableicons/dragwidget.cpp

@@ -114,18 +114,13 @@ void DragWidget::mousePressEvent(QMouseEvent *event)
     drag->setHotSpot(event->position().toPoint() - child->pos());
 //! [3]
 
-    QPixmap tempPixmap = pixmap;
-    QPainter painter;
-    painter.begin(&tempPixmap);
-    painter.fillRect(pixmap.rect(), QColor(127, 127, 127, 127));
-    painter.end();
-
-    child->setPixmap(tempPixmap);
+    child->setParent(nullptr);
 
     if (drag->exec(Qt::CopyAction | Qt::MoveAction, Qt::CopyAction) == Qt::MoveAction) {
-        child->close();
+        delete child;
     } else {
+        child->setParent(this);
+        child->move(event->position().toPoint() - drag->hotSpot());
         child->show();
-        child->setPixmap(pixmap);
     }
 }