Don't set the mouse cursor for items that are disabled

As with widgets, items that are disabled should not receive any input
events.

Similar to QGraphicsScene, which ignores disabled items when handling
mouse presses, the view should also ignore them when handling mouse
moves to update the cursor.

Since QGraphicsView only adjusts the cursors on mouse moves, reenabling
an item that is currently under the mouse will not change the cursor.
This is consistent with other changes of item attributes that would
position the item under the mouse (such as moving it). The overhead of
hit-testing items for every such attribute change would be too large,
and applications can generate a mouse move event if they really need
to adjust the cursor in all situations.

[ChangeLog][QtWidgets][QGraphicsView] Ignore disabled items when setting
the mouse cursor.

Fixes: QTBUG-76765
Change-Id: Ifcd31fc0581e8421e58eeb436a55b031909eed7e
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 9 insertions, 0 deletions

diff --git a/tests/auto/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp b/tests/auto/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp
index af4b6c9e4a..3260e09943 100644
--- a/tests/auto/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp
+++ b/tests/auto/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp
@@ -4219,6 +4219,15 @@ void tst_QGraphicsItem::cursor()
     }
 
     QTRY_COMPARE(view.viewport()->cursor().shape(), viewportShape);
+
+    item1->setEnabled(false);
+    {
+        QTest::mouseMove(view.viewport(), item1Center);
+        QMouseEvent event(QEvent::MouseMove, item1Center, view.viewport()->mapToGlobal(item1Center), Qt::NoButton, 0, 0);
+        QApplication::sendEvent(view.viewport(), &event);
+    }
+
+    QTRY_COMPARE(view.viewport()->cursor().shape(), viewportShape);
 }
 #endif
 /*