Remembering selection prevents next level from loading

When selecting an item from the root level, the next level is automatically loaded and shown in a new list. However, once you add an item to the dropbox, all the lists disappear except the root one. This list keeps its selection which prevents you from loading the next level unless you choose another item first. This makes sense as the onchange event cannot fire unless the selection has actually changed. In order to temporarily solve this, the patch simply resets the selection in all the lists once an item has been added to the dropbox. This forces the user to always start from scratch when adding a new item which is preferable.