I and several others here have looked at the tuxedo product and like it for the most part.
The biggest issue we see right away is having to scroll right to log out. Many people do not have screens wider than 640 pixels and even those that do tend to like narrow windows. Our first suggestion is to move logout to the file menu and put it on the left side of the screen somewhere.
The second item is the date format. That should be configurable by the end user and should probably default to mm/dd/yyyy (since most Americans think the world revolves around them

The last from our initial looksee is that the columns do not have enough whitespace between them. The subject tends to run into the sender address and you can't tell were one ends and the other begins, especially in the narrow windows.
Azander