>The only problem that I think the side by side layout will have is when a thread grows deep enough.

Right-O

>The thing is that right now we have approx 2/3rds of the screen height for the message body and 1/3 for teh message tree. 3/4 of the width is available for the message body and the tree. Your example is givin us more height for the tree but less width (and the tree needs the width more than the height).

The heights can be changed with the Frame Splitter so that doens't really matter. I usually max out the top frame selecting messages, then after clicking on view marked, I max the bottom...

>The message body doesn;t make much difference whether it gets height or width as either one allows more text (one by more lines and the other by more columns).

... but I would say that the messages are nice to be wide too, for viewing code, ect.