Related: #i124856# guard against crash

Patch By: hanya
Review By: jsc

(cherry picked from commit efe87c0d)

Conflicts:
	accessibility/source/standard/vclxaccessiblebox.cxx

Change-Id: I24fd4278406dacea33230cc1bf1528e3c5aaedf2

accessibility/source/standard/vclxaccessiblebox.cxx

@@ -176,7 +176,7 @@ void VCLXAccessibleBox::ProcessWindowEvent (const VclWindowEvent& rVclWindowEven
         case VCLEVENT_COMBOBOX_SELECT:
         {
              VCLXAccessibleList* pList = static_cast<VCLXAccessibleList*>(m_xList.get());
-             if (pList != NULL)
+             if (pList != NULL && m_xText.is())
              {
                 Reference<XAccessibleText> xText (m_xText->getAccessibleContext(), UNO_QUERY);
                 if ( xText.is() )