How do I delete a monitor?

This is much harder then it seems. Using the built in "Partition Details of the Device (%)" monitor that comes with OpManager. I know OpManager has problems with the + symbol in names. One of our mounts has a + in it. That mount is detected and monitored by OpManager. I need to delete it, but OpManager is un able to delete that monitor, no matter how many times I delete it. OpManager always returns "Graph deleted successfully" When I can see that it is still there and not delete, and I get the following E-Mails about the mount.

Message: Partition Details of the Device (%) for /linux_auto/nif+tools is 91 Percentage, threshold value for this monitor is 90 Percentage
Device: Makena
Category: Server
Error Condition: Trouble
Generated at: Jun 16,2008 03:25:07 PM

So I try to edit the threshold and get this error: