Automatic list alignment based on viewport boundaries is a feature I'd like to add in a future version.

In the meantime, the alignment of the result list is manually configurable using the "align" config attribute, which is documented here: http://developer.yahoo.com/yui/3/autocomplete/#alignment

Here's an example that demonstrates how to align the result container above the input node instead of under it: http://jsfiddle.net/rgrove/6sREw/

Thanks for the hint. As I am using the AutoComplete widget in a bigger standard one in my web application, I'd have to make the alginment automatic so I may prefer to keep it this way 'till the next update. FYI, the bigger widget uses AutoComplete to search content in an existing ComboBox. I'd also appreciate that this kind of Widget exists in a future version on a standard Library like YUI because browser's support for ComboBoxes makes it very difficult to search properly in a large amount of items.

Moving from 3.NEXT to BACKLOG.