Allow lookup field events (click, search, more records, etc.) to be redirected to a custom handlers when user requests to lookup more records via the search button or more records or from business process.

We currently override the contact lookup process to be a custom search and select wizard with complex logic to retrieve likely candidates and rank them by best match. Something that not possible via FetchXML using existing filters.

In the web interface this was possible in unsupported hack of overriding the JavaScript events and launching custom html web resources. But in UCI not so possible.

I would be happy with being able to define a PCF by extending the lookup control, but PCF doesn't seem to have an extensibility model for controls besides rewriting them from scratch.