I put in a vote for this too. It would be useful, especially in cases where schools use LS, and we have many users -- it would make it much easier to find a specific user if there was a filter available (like we have for surveys).

I second this request. It's tagged as a feature request, but I think it's critical to add it. The way it is now greatly affects usability for administrators, when the amount of users is greater than 100. I certainly feel the lack of it in my day-to-day work administering our instance with 564 user accounts.

that should be easy and fast to do.

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=27181