Set pane size

Maybe something like this, you set the min and max height to the same size, then save the splitter positions, then chnage the min\max height\width back to what you want the user to be able to resize:

pPane->SetMinTrackSize(CSize(150, 150));
pPane->SetMaxTrackSize(CSize(150, 150));

GetDockingPaneManager()->NormalizeSplitters();

pPane->SetMinTrackSize(CSize(50,50));
pPane->SetMaxTrackSize(CSize(32000,20));

You can see the PaneSample for more on how to do this.

Look at this function:

void CMainFrame::OnMinMaxSamlpe()
{
    m_bMinMaxSample = !m_bMinMaxSample;

    if (m_bMinMaxSample)
    {
        CXTPDockingPane* pPane = m_paneManager.FindPane(IDR_PANE1);
        ASSERT(pPane);
        pPane->SetMinTrackSize(CSize(100, 100));
        pPane->SetMaxTrackSize(CSize(150, 150));

        pPane = m_paneManager.FindPane(IDR_PANE2);
        ASSERT(pPane);
        pPane->SetMinTrackSize(CSize(130, 130));
        pPane->SetMaxTrackSize(CSize(130, 130));
    }
    else
    {
        CXTPDockingPane* pPane = m_paneManager.FindPane(IDR_PANE1);
        ASSERT(pPane);
        pPane->SetMinTrackSize(CSize(0, 0));
        pPane->SetMaxTrackSize(CSize(32000, 32000));

        pPane = m_paneManager.FindPane(IDR_PANE2);
        ASSERT(pPane);
        pPane->SetMinTrackSize(CSize(0, 0));
        pPane->SetMaxTrackSize(CSize(32000, 32000));
    }

    for (int i = 0; i < sizeof(m_wndPanes) / sizeof(m_wndPanes[0]); i++)
    {
        if (m_wndPanes.m_hWnd)
        {
            m_wndPanes.OnSize(0, 0, 0);
            m_wndPanes.RedrawWindow();

        }
    }
    GetDockingPaneManager()->RedrawPanes();
}