jQueryUI autocomplete not working with dialog and zIndex

Question

I ran into an interesting issue with jQueryUI autocomplete in a dialog box.

My dialog HTML looks like this:

Answer 1

Try setting the appendTo option to "#copy_dialog":

$(/** autocomplete-selector **/)
    .autocomplete("option", "appendTo", "#copy_dialog");

This option specifies which element the autocomplete menu is appended to. By appending the menu to the dialog, the menu should inherit the correct z-index.