I've noticed when I search for a user that doesn't exist or when I clear the search with the X the screen begins to redraw or fresh several times. Looks very strange.
I noticed that search results did not work at first. Over time results would populate. For example I searched for 'da' hoping to get david but no results appeared. I tried 'david' I got a list. Later I tried 'da' again and it worked. Same with someone lastname. After playing with search for about 5-10 mins I started to see consistent results.
Feature request - search for username