Avoid crash-reporter crash.

http://crashreport.libreoffice.org/stats/crash_details/f5086a7d-3c67-46e4-945e-e0882a604eee

Change-Id: Ic9ceed2e736a4ad1c155a31d3b2dc453e6a562aa
Reviewed-on: https://gerrit.libreoffice.org/52119Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>

sw/source/uibase/utlui/navipi.cxx

@@ -945,6 +945,9 @@ IMPL_LINK( SwNavigationPI, MenuSelectHdl, Menu *, pMenu, bool )
 
 void SwNavigationPI::UpdateListBox()
 {
+    if (isDisposed())
+        return;
+
     m_aDocListBox->SetUpdateMode(false);
     m_aDocListBox->Clear();
     SwView *pActView = GetCreateView();

vcl/source/window/window.cxx

@@ -2992,15 +2992,20 @@ void Window::Scroll( long nHorzScroll, long nVertScroll,
 
 void Window::Flush()
 {
-
-    const tools::Rectangle aWinRect( Point( mnOutOffX, mnOutOffY ), Size( mnOutWidth, mnOutHeight ) );
-    mpWindowImpl->mpFrame->Flush( aWinRect );
+    if (mpWindowImpl)
+    {
+        const tools::Rectangle aWinRect( Point( mnOutOffX, mnOutOffY ), Size( mnOutWidth, mnOutHeight ) );
+        mpWindowImpl->mpFrame->Flush( aWinRect );
+    }
 }
 
 void Window::SetUpdateMode( bool bUpdate )
 {
-    mpWindowImpl->mbNoUpdate = !bUpdate;
-    CompatStateChanged( StateChangedType::UpdateMode );
+    if (mpWindowImpl)
+    {
+        mpWindowImpl->mbNoUpdate = !bUpdate;
+        CompatStateChanged( StateChangedType::UpdateMode );
+    }
 }
 
 void Window::GrabFocus()