QmlDesigner: Fix Components lib wrong scrolling after drag-n-drop

Change-Id: Ibd3f3c155496443eac0accf468280a15cad51351
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>

share/qtcreator/qmldesigner/itemLibraryQmlSources/ItemsView.qml

@@ -235,7 +235,7 @@ Item {
             id: verticalScrollView
             anchors.fill: parent
             clip: true
-            interactive: !itemContextMenu.opened && !moduleContextMenu.opened
+            interactive: !itemContextMenu.opened && !moduleContextMenu.opened && !rootView.isDragging
 
             onContentHeightChanged: {
                 var maxPosition = Math.max(contentHeight - verticalScrollView.height, 0)
@@ -352,7 +352,7 @@ Item {
                 width: 270
                 height: parent.height
                 clip: true
-                interactive: !itemContextMenu.opened && !moduleContextMenu.opened
+                interactive: !itemContextMenu.opened && !moduleContextMenu.opened && !rootView.isDragging
 
                 onContentHeightChanged: {
                     var maxPosition = Math.max(contentHeight - horizontalScrollView.height, 0)
@@ -457,6 +457,8 @@ Item {
                 id: itemScrollView
                 width: itemsView.width - 275
                 height: itemsView.height
+                interactive: !itemContextMenu.opened && !moduleContextMenu.opened && !rootView.isDragging
+
                 onContentHeightChanged: {
                     var maxPosition = Math.max(contentHeight - itemScrollView.height, 0)
                     if (contentY > maxPosition)

src/plugins/qmldesigner/components/itemlibrary/itemlibrarywidget.cpp

@@ -105,6 +105,10 @@ bool ItemLibraryWidget::eventFilter(QObject *obj, QEvent *event)
                 m_itemToDrag = {};
             }
         }
+    } else if (event->type() == QMouseEvent::MouseButtonRelease) {
+        m_itemToDrag = {};
+
+        setIsDragging(false);
     }
 
     return QObject::eventFilter(obj, event);
@@ -366,12 +370,21 @@ void ItemLibraryWidget::handlePriorityImportsChanged()
     }
 }
 
+void ItemLibraryWidget::setIsDragging(bool val)
+{
+    if (m_isDragging != val) {
+        m_isDragging = val;
+        emit isDraggingChanged();
+    }
+}
+
 void ItemLibraryWidget::startDragAndDrop(const QVariant &itemLibEntry, const QPointF &mousePos)
 {
     // Actual drag is created after mouse has moved to avoid a QDrag bug that causes drag to stay
     // active (and blocks mouse release) if mouse is released at the same spot of the drag start.
     m_itemToDrag = itemLibEntry;
     m_dragStartPoint = mousePos.toPoint();
+    setIsDragging(true);
 }
 
 bool ItemLibraryWidget::subCompEditMode() const

src/plugins/qmldesigner/components/itemlibrary/itemlibrarywidget.h

@@ -44,6 +44,9 @@ class ItemLibraryWidget : public QFrame
 public:
     Q_PROPERTY(bool subCompEditMode READ subCompEditMode NOTIFY subCompEditModeChanged)
 
+    // Needed for a workaround for a bug where after drag-n-dropping an item, the ScrollView scrolls to a random position
+    Q_PROPERTY(bool isDragging MEMBER m_isDragging NOTIFY isDraggingChanged)
+
     ItemLibraryWidget(AsynchronousImageCache &imageCache);
     ~ItemLibraryWidget();
 
@@ -76,6 +79,7 @@ public:
 signals:
     void itemActivated(const QString &itemName);
     void subCompEditModeChanged();
+    void isDraggingChanged();
 
 protected:
     bool eventFilter(QObject *obj, QEvent *event) override;
@@ -86,6 +90,8 @@ private:
 
     void updateSearch();
     void handlePriorityImportsChanged();
+    void setIsDragging(bool val);
+
     static QString getDependencyImport(const Import &import);
 
     QTimer m_compressionTimer;
@@ -107,6 +113,7 @@ private:
     QString m_filterText;
     QPoint m_dragStartPoint;
     bool m_subCompEditMode = false;
+    bool m_isDragging = false;
 
     inline static int HORIZONTAL_LAYOUT_WIDTH_LIMIT = 600;
 };