A self built performance dashboard keeps coming back after logging out / in, even after deleting it

I've created a performance dashboard in a Unity system (Unisphere) containing only the LUNs I want to observe during a set period of time and it stays available even after I log out and log back in the day after. When I delete this dashboard it's gone (of course), but when I log out and log back in, it re-appears. I can't get rid of it! I've tried renaming it, deleting it dozens of times, but every single time when I log back in it's there. The LUNs I was observing in this dashboard are already gone since over a year or so, but this dashboard keeps re-appearing. Deleting it only works for the session I'm in and when I log out / in, it's back. Can anyone help me get rid of this dashboard?