Autocomplete and Master page issue

Autocomplete and Master page issue

Hi, I have UI autocomplete assigned to a text box using a master page. When autocomplete shows, and I tried to scroll the page, the listbox item/element also scrolls within the page. Is there a way to make the autocomplete listbox element fixed to its designated textbox control? It seems the autocomplete listbox is floating (in a way).
 
I tried it without the master page, and it works.