CXTPDockingPaneLayout::DoPropExchange() filtering.

Hi All

When I'm saving the layout of my docking panes I want to filter out unwanted panes so that they don't get modified when I do a restore later on. In the following code snippet I'm attempting to do this. I'm creating a new pane layout object, removing the docking panes I don't want from the pane list, and then doing a property exchange on that.

CXTPPropExchangeSection pxDockingPane(pPX->GetSection(_T("DockingPane")));
if (!pPX->IsLoading ())
  {
  CXTPDockingPaneLayout *pLayout = m_paneManager.CreateLayout ();
  m_paneManager.GetLayout (pLayout);
  if (pLayout)
    {
    std::set<int> idSet;
    idSet.insert (ID_PANE_1);
    idSet.insert (ID_PANE_2);
    idSet.insert (ID_PANE_3);

    // Remove unwanted panes before exchange.
    CXTPDockingPaneInfoList cache;
    CXTPDockingPaneInfoList &paneList = pLayout->GetPaneList ();
    POSITION pos = paneList.GetTailPosition();
    while (pos)
      {
      CXTPDockingPane* pPane = paneList.GetAt (pos);
      if (idSet.find (pPane->GetID ()) != idSet.end ())
        {
        cache.AddTail (paneList.GetAt (pos));
        paneList.RemoveAt (pos);
        }
      paneList.GetPrev (pos);
      }
    pLayout->DoPropExchange (&pxDockingPane);
    delete pLayout;
    }
  }

And here is the generated layout…

<Settings CompactMode="1">
  <CustomLayout>
    <DockingPane>
      <Summary Panes="21" TopContainer="4" Client="9"/>
      <Pane-1 Type="0" DockingCX="220" DockingCY="150" Title="Forms\n" ID="40" DockingHolder="7" LastHolder="7" MinTrackX="100" MinTrackY="100"/>
      <Pane-2 Type="0" DockingCX="200" DockingCY="120" Title="MyApplication:2\n\n" ID="501" Options="16" DockingHolder="10" FloatingHolder="13" LastHolder="13"/>
      <Pane-3 Type="5" Direction="0" Panes="0"/>
      <Pane-4 Type="2" Panes="1" Pane-1="5"/>
      <Pane-5 Type="2" DockingCX="1280" DockingCY="723" Horiz="1" Panes="2" Pane-1="6" Pane-2="8"/>
      <Pane-6 Type="2" DockingCX="223" DockingCY="876" Panes="1" Pane-1="7"/>
      <Pane-7 Type="1" DockingCX="220" DockingCY="494" Panes="3" Pane-1="0" Pane-2="0" Pane-3="0"/>
      <Pane-8 Type="2" DockingCX="1178" Panes="2" Pane-1="9" Pane-2="10"/>
      <Pane-9 Type="4"/>
      <Pane-10 Type="1" DockingCX="200" DockingCY="120" Panes="0"/>
      <Pane-11 Type="3" WindowRectTopPos="49" WindowRectBottomPos="429" WindowRectLeftPos="775" WindowRectRightPos="1359" TopContaner="12"/>
      <Pane-12 Type="2" DockingCX="200" DockingCY="120" Horiz="1" Panes="1" Pane-1="13"/>
      <Pane-13 Type="1" DockingCX="200" DockingCY="120" Panes="1" Selected="2" Pane-1="2"/>
    </DockingPane>
  </CustomLayout>
</Settings>

All good so far. So now for my problem.

Loading the saved layout crashes. I think that it's because <Summary Panes="21" TopContainer="4" Client="9"/> is wrong (it is still referring to the original number of panes before I removed some of them). Unfortunately that value is retrieved from a private member in the CXTPDockingPaneLayout class so I can't change it. I guess I could just change the XML but that seems pretty hacky.

Any thoughts / ideas? Ideally I'd like to override CXTPDockingPaneLayout::_Save but obviously that has been abstracted away for good reasons.