Resolves: fdo#65536 check if builder is NULL

Change-Id: Ieabd56d6da06b480ade662a55aebd35d0769f2ea

cui/source/tabpages/paragrph.cxx

@@ -646,7 +646,7 @@ namespace
             pChild = pChild->GetWindow(WINDOW_NEXT))
         {
             VclBuilderContainer *pPeer = dynamic_cast<VclBuilderContainer*>(pChild);
-            if (pPeer != pPage)
+            if (pPeer != pPage && pPeer->hasBuilder())
             {
                 Window *pOtherGrid = pPeer->get<Window>("maingrid");
                 Window *pOurGrid = pPage->get<Window>("maingrid");

include/vcl/builder.hxx

@@ -381,6 +381,7 @@ public:
     VclBuilderContainer();
     virtual ~VclBuilderContainer();
     static OUString getUIRootDir();
+    bool hasBuilder() const { return m_pUIBuilder != NULL; }
     template <typename T> T* get(T*& ret, OString sID)
     {
         return m_pUIBuilder->get<T>(ret, sID);