Turn off all border styles for the inner window

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_4_BRANCH@20077 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/listctrl.cpp

@@ -4663,7 +4663,7 @@ bool wxGenericListCtrl::Create(wxWindow *parent,
         return FALSE;
 
     // don't create the inner window with the border
-    style &= ~wxSUNKEN_BORDER;
+    style &= ~wxBORDER_MASK;
 
     m_mainWin = new wxListMainWindow( this, -1, wxPoint(0,0), size, style );