QmlDesigner.DocumentManager: Do not scatter items in layouts

Items in layouts do not need to be positioned.

Change-Id: I2bf0c83be48bd9aad11aab74e56e8a27f962214a
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>

src/plugins/qmldesigner/components/integration/designdocument.cpp

@@ -422,6 +422,8 @@ void DesignDocument::cutSelected()
 
 static void scatterItem(const ModelNode &pastedNode, const ModelNode &targetNode, int offset = -2000)
 {
+    if (targetNode.metaInfo().isValid() && targetNode.metaInfo().isLayoutable())
+        return;
 
     bool scatter = false;
     foreach (const ModelNode &childNode, targetNode.directSubModelNodes()) {