diff --git a/5.6.3/qtbase/src/gui/accessible/qaccessibleobject.cpp b/5.6.3/qtbase/src/gui/accessible/qaccessibleobject.cpp
index dcf4624..2fa16c9 100644
--- a/5.6.3/qtbase/src/gui/accessible/qaccessibleobject.cpp
+++ b/5.6.3/qtbase/src/gui/accessible/qaccessibleobject.cpp
@@ -119,7 +119,7 @@ QAccessibleInterface *QAccessibleObject::childAt(int x, int y) const
     for (int i = 0; i < childCount(); ++i) {
         QAccessibleInterface *childIface = child(i);
         Q_ASSERT(childIface);
-        if (childIface->rect().contains(x,y))
+        if (childIface->isValid() && childIface->rect().contains(x,y))
             return childIface;
     }
     return 0;