diff --git a/src/gui/kernel/qpointingdevice.cpp b/src/gui/kernel/qpointingdevice.cpp
index 126c2838d4e..e43cb7013a3 100644
--- a/src/gui/kernel/qpointingdevice.cpp
+++ b/src/gui/kernel/qpointingdevice.cpp
@@ -498,6 +498,7 @@ void QPointingDevicePrivate::setExclusiveGrabber(const QPointerEvent *event, con
         qWarning() << "point is not in activePoints" << point;
         return;
     }
+    Q_ASSERT(persistentPoint->eventPoint.id() == point.id());
     if (persistentPoint->exclusiveGrabber == exclusiveGrabber)
         return;
     auto oldGrabber = persistentPoint->exclusiveGrabber;
diff --git a/src/gui/kernel/qpointingdevice_p.h b/src/gui/kernel/qpointingdevice_p.h
index a9c4a1fa846..f633327f27c 100644
--- a/src/gui/kernel/qpointingdevice_p.h
+++ b/src/gui/kernel/qpointingdevice_p.h
@@ -108,7 +108,7 @@ public:
     void clearPassiveGrabbers(const QPointerEvent *event, const QEventPoint &point);
     void removeGrabber(QObject *grabber, bool cancel = false);
 
-    using EventPointMap = QFlatMap<int, EventPointData>;
+    using EventPointMap = QVarLengthFlatMap<int, EventPointData, 20>;
     mutable EventPointMap activePoints;
 
     QPointingDeviceUniqueId uniqueId;