docking crash fix patch applied

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43436 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/aui/framemanager.cpp

@@ -2177,8 +2177,6 @@ void wxAuiManager::Update()
     wxSizer* sizer;
     int i, pane_count = m_panes.GetCount();
 
-    // delete old sizer first
-    m_frame->SetSizer(NULL);
 
     // destroy floating panes which have been
     // redocked or are becoming non-floating
@@ -2227,6 +2225,9 @@ void wxAuiManager::Update()
     }
 
 
+    // delete old sizer first
+    m_frame->SetSizer(NULL);
+
     // create a layout for all of the panes
     sizer = LayoutAll(m_panes, m_docks, m_uiparts, false);