It's not immediately obvious that you can press on this static text to
bring up the user's details. This isn't a problem with the avatar - for
example - because it has a pointing hand cursor. Let's do the same here.
(cherry picked from commit 0ccfe7d991)
Constructing the timezone string is relatively heavy and is done for each delegate, even when the tooltip is never shown
(cherry picked from commit 42cec7d5ba)
