Extend selections in QGraphicsView when selection extension key down

If the user has some objects selected and holds down the "extend selection"
key (Control on Windows, Command on Mac OS X), clicking and dragging a
rubber band selection deselects the current selection.  This is
counter-intuitive and confusing for users.

This commit fixes the behavior so users can extend selections using the
rubber band when the proper key is held down.

Task-number: QTBUG-6523
Change-Id: Ieda4aaa50adb351c0405f5cb8aae23332eec58a9
Reviewed-by: Andreas Aardal Hanssen <andreas@hanssen.name>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/widgets/graphicsview/qgraphicsscene.h b/src/widgets/graphicsview/qgraphicsscene.h
index 6cd5da00c8..03df18fbce 100644
--- a/src/widgets/graphicsview/qgraphicsscene.h
+++ b/src/widgets/graphicsview/qgraphicsscene.h
@@ -177,6 +177,8 @@ public:
     QPainterPath selectionArea() const;
     void setSelectionArea(const QPainterPath &path, const QTransform &deviceTransform);
     void setSelectionArea(const QPainterPath &path, Qt::ItemSelectionMode mode = Qt::IntersectsItemShape, const QTransform &deviceTransform = QTransform());
+    void setSelectionArea(const QPainterPath &path, Qt::ItemSelectionOperation selectionOperation, Qt::ItemSelectionMode mode = Qt::IntersectsItemShape, const QTransform &deviceTransform = QTransform());
+    // ### Qt6 merge the last 2 functions and add a default: Qt::ItemSelectionOperation selectionOperation = Qt::ReplaceSelection
 
     QGraphicsItemGroup *createItemGroup(const QList<QGraphicsItem *> &items);
     void destroyItemGroup(QGraphicsItemGroup *group);