don't crash if editing of the cell wasn't started for whatever reason (patch 502692)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@14341 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/grid.cpp

@@ -5832,8 +5832,15 @@ void wxGrid::OnKeyDown( wxKeyEvent& event )
                          || editor->IsAcceptedKey(event) )
                     {
                         EnableCellEditControl();
+
+                        // the editor could be not shown for a variety of
+                        // reasons (i.e. blocked by the app or whatever), so
+                        // check if it really was created
+                        if ( m_cellEditCtrlEnabled )
+                        {
                             editor->StartingKey(event);
                         }
+                    }
                     else
                     {
                         event.Skip();