diff --git a/include/wx/string.h b/include/wx/string.h
index 04483f3e12..0462f4f2e8 100644
--- a/include/wx/string.h
+++ b/include/wx/string.h
@@ -3126,7 +3126,7 @@ void wxStringIteratorNode::DoSet(const wxString *str,
                                  wxStringImpl::const_iterator *citer,
                                  wxStringImpl::iterator *iter)
 {
-    m_next = m_prev = NULL;
+    m_prev = NULL;
     m_iter = iter;
     m_citer = citer;
     m_str = str;
@@ -3137,6 +3137,10 @@ void wxStringIteratorNode::DoSet(const wxString *str,
         if ( m_next )
             m_next->m_prev = this;
     }
+    else
+    {
+        m_next = NULL;
+    }
 }
 
 void wxStringIteratorNode::clear()