Cannot display some types of HTML based messages. Most instances I've noticed the problem with .NET Mime encapsulated HTML messages. The message appears/readable if preferences are set to view in Text mode, but some data is lost. If the link "View in HTML" is clicked on, the message fails to display at all.
There may be other instances where HTML based messages are not displayed correctly. Most cases switching to text mode is the work-around.
Oddly, the same message can be viewed using squirrelmail and is rendered in HTML mode properly. (sorry) So the problem seems confined to the HTML rendering engine usermin uses.
Problem appears in 1.340 and previous versions at least as early as 1.300 when I first started noticing the problem. HTML viewing problem is present whether using IE6, Opera 9.27, or Mozilla 2.0.14 browsers.
Unfortunately, I cannot submit a email example as the ones it failed on contained confidential information from travel reservation sites, or credit card purchases. (sorry) If I come across other instances that are not confidential I will gladly forward them on as test examples.