Strange behaviour of the Mootools AutocompletionAndZoom component

When the Mootools library is loaded by the component (after OpenLayers), some mouse events on the list aren't loaded .

For example : click on a word of the list do nothing
mouseover event on words of the list doesn't exist

When Mootools library is loaded in the head tag (before OpenLayers), all works fine. Conflict between Mootools and OL events?