Javascript errors with inbox block prevents any link on page from being clicked

Problem/Motivation

There are several js errors with the inbox block

1. on setActiveThread() container is undefined when the page loads.
2. $(this) inside the each() loops is returning the window and not the element it's looping over, and the call to preventDefault() inside the click handlers are happening for the entire page making and link unclickable
3. the load more threads link is not working.

I believe #3424499: Stuck on undefined URL is related

Proposed resolution

All of these seem to be related, and after some poking around I see that $(this) should be replaced with the elements arg from the each() loop to target the correct element in private_message_inbox_block.js

MR incoming.