IssueTracker

PageEvent.Drop currently carries info for a single LoadState of a single LoadType. This deviates from PageEvent.Insert and PageEvent.LoadStateUpdate that have been recently refactored to carry full source/mediator load states.

It might be a good idea to have Drop events also carry full source/mediator states. This would allow:
1. unifying all PageEvent pipelines to send latest LoadStates from Fetcher, thus removing the burden from presenters to parse any implied updates
2. removal of redundant helper functions needed to parse the single LoadState update from Drop events