Mark First Match in check box Combobox

[Dhamodharan]

Hi,
I am using multi select combobox by enabling CheckBoxes="true".
My requirement is 
I should able to select items by mark first match. it allows only when no items in the text box. if I had items mark first match does not works. as showed in attached notes
 
  

[Dhamodharan]

Hi,
My requirement is fulfilled by using AutoCompleteSeparator =","





Thanks