tdf#92055 - make ImplBorderWindow more tolerant of post-dispose events.

Change-Id: I9556c920e6fc8b5595eee6bd00d36669e1684e25
Reviewed-on: https://gerrit.libreoffice.org/16892
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Michael Meeks <michael.meeks@collabora.com>
diff --git a/vcl/source/window/brdwin.cxx b/vcl/source/window/brdwin.cxx
index 8695054..75523ef 100644
--- a/vcl/source/window/brdwin.cxx
+++ b/vcl/source/window/brdwin.cxx
@@ -1851,27 +1851,32 @@ void ImplBorderWindow::dispose()

void ImplBorderWindow::MouseMove( const MouseEvent& rMEvt )
{
    mpBorderView->MouseMove( rMEvt );
    if (mpBorderView)
        mpBorderView->MouseMove( rMEvt );
}

void ImplBorderWindow::MouseButtonDown( const MouseEvent& rMEvt )
{
    mpBorderView->MouseButtonDown( rMEvt );
    if (mpBorderView)
        mpBorderView->MouseButtonDown( rMEvt );
}

void ImplBorderWindow::Tracking( const TrackingEvent& rTEvt )
{
    mpBorderView->Tracking( rTEvt );
    if (mpBorderView)
        mpBorderView->Tracking( rTEvt );
}

void ImplBorderWindow::Paint( vcl::RenderContext& rRenderContext, const Rectangle& )
{
    mpBorderView->DrawWindow(rRenderContext, BORDERWINDOW_DRAW_ALL);
    if (mpBorderView)
        mpBorderView->DrawWindow(rRenderContext, BORDERWINDOW_DRAW_ALL);
}

void ImplBorderWindow::Draw( const Rectangle&, OutputDevice* pOutDev, const Point& rPos )
{
    mpBorderView->DrawWindow(*pOutDev, BORDERWINDOW_DRAW_ALL, &rPos);
    if (mpBorderView)
        mpBorderView->DrawWindow(*pOutDev, BORDERWINDOW_DRAW_ALL, &rPos);
}

void ImplBorderWindow::Activate()