xrestop usage

[stan]

WE have deployed a number of ^ CURRENT machines as what are basicly kosoks.
We are seeing some issues with Firefox memory usage growth on long running
systems.

Soem googling has lead to a link sugestiong a possible solution. The
linkalos recomends using xrestop to examine the potential issue.

I've built this tool from ports, but when I run it it gives me an error
message like this:

xrestop: XResQueryExtension failed. Display Missing XRes extension ?

So, it appears that I eed an extension fo xorg. 

How can I add this extnsion?

-- 
Unix is very simple, but it takes a genius to understand the simplicity.
(Dennis Ritchie)