Ajax toolKit AutoComplete Extender dispaly problem

hi every body ,

i am working on ajax toolkit autocomplete extender it working fine when i am using this without master page but it display wrong way when i use with master page

ex:

 suppose my service return string array  with values {key1,key2,key3....}

when i use with out master page it displays like :   key1
   key2
  key3
  .
  .
when i use with master page it displays like : key1key2key3... (but while select individual selection is possible )

i am using same coding for both difference is just with master page and with out master page


what is the problem here how can i overcome to that one.

Thanks,
M.Koteswara Rao.