change the settings and again revert back once resolved.

check below details for the same.

Changing the Default on a Permanent Basis
Since the bpdbjobs database resets to default conditions upon reboot or cycling NetBackup Services, you may want a more permanent means of indicating how long to keep jobs in the Activity Monitor.
Use the following method to add new registry key(s) to
HKEY_LOCAL_MACHINE\SOFTWARE\VERITAS\NetBackup\
CurrentVersion\Config
To do so safely, from a command window, run:
install_path/veritas/netbackup/bin/admincmd
echo KEEP_JOBS_HOURS = 192 | bpsetconfig
Where 192 is the number of hours that all jobs (both successful and unsuccessful) will be kept in the jobs database (or Activity Monitor display).
To retain only successful jobs, enter:
echo KEEP_JOBS_SUCCESSFUL_HOURS = 192 | bpsetconfig
Note The retention period values are measured against the time the job ended.

for more information refer to page no 349 from admin guide...

hope it helps...

I have had flakey things happen with the activity monitor. I simply exit the monitor and start a new one.

hi

i alredy restart activity monitor so many times ..

Try to isolate if the problem is in the gui or jobdb.

To do this, type the following commands:

bpdbjobs -summary (see how many queued jobs you see)
bpdbjobs | grep <job id> (take the job id of duplication job from GUI)
If the jobs appears here also, then probably there is nothing wrong with GUI.

bpdbjobs -cancel <job id> (try to cancel the job with this command).
 
If even this does not work out for yo, restart netbackup services and see if the jobs go to "done" state from "queued"

Some help on bpdbjobs:

http://seer.entsupport.symantec.com/docs/235842.htm