Bugfixes

Fixed 2 bugs:

• when a search widget was inside a context object that could change, it was possible for it to register itself more than once, leading to duplicated xpath constraints applied to a grid (end result: slower queries)
• when lists can be added dynamically during or after page load, for example with a list inside of a list, the search widgets wouldn't find new lists to search on. This has been fixed, so on each search there's a query looking for all eligible lists