Let's say you use autocomplete with the 'mutliple' option and 'minChar' set to 0.

If you focus the input element with autocompletion and type the 'arrow down' button you get a complete list of suggestions from the backend. I choose one from the list which will be automatically added to the input field including the sperator (default ", ") at the end.

Then I type again the 'arrow down' button to fetch the complete list again. That's where the error happens. I only get a list with one item, the item selected before.

My solution to this problem:

Change line 255 in jquery.autocomplete.js from:

if ( $.trim(value) ) )

to:

if ( $.trim(value) || (!$.trim(value) && options.minChars == 0) )

For this solution works - don't know if there are any side effects?