diff --git a/scim-wnn/src/scim_wnn_imengine.cpp b/scim-wnn/src/scim_wnn_imengine.cpp
index 6582a16..222ff1d 100644
--- a/scim-wnn/src/scim_wnn_imengine.cpp
+++ b/scim-wnn/src/scim_wnn_imengine.cpp
@@ -254,9 +254,10 @@
         update_preedit_caret(m_rk.getPos());
         return(true);
     }
-    if (key.code == SCIM_KEY_space) {
-        m_convList.pos ++;
+    if ((key.code == SCIM_KEY_space) || (key.code == SCIM_KEY_Down) || (key.code == SCIM_KEY_Up)) {
+        key.code == SCIM_KEY_Up ? m_convList.pos --: m_convList.pos ++;
         if (m_convList.pos >= m_convList.count) m_convList.pos = 0;
+        else if (m_convList.pos < 0) m_convList.pos = m_convList.count - 1;
 
         wnn.select(m_convList.pos);
         update_preedit_string(wnn.getText(),wnn.getAttributeList());