Disk Usage graph legend missing a partition

I am running xymon 4.3.25 on Ubuntu. On the disk usage page I can see all
of my partitions but in the graph it is not showing one of the partitions.

On disk page I have
/stand
/u3
/u2
/u
/

But in the graph the legend shows
/
/stand
/u2

Where do I go to make sure all of the partitions are showing up in the
graph?

It came to my attention today when one partition hit the panic level and as
I was correcting it I noticed the partition missing in the graph.
-- 
John J. Boris, Sr.