Chrisb222's post in How to turn off cross section callouts for certain layer sets? was marked as the answer
Try turning off the layer "Cameras, Cross Section & Elevation"
In this pic it looks like the camera view is active (open), and that you have "Always Display Active Cameras" checked in your 3D View defaults.
That will cause the callout for any open camera to always appear, even if the layer is off, until the camera view is closed.
Not sure where it is in X7 (been awhile) but look for a Default setting something like this:
...and uncheck it, if you don't want to see open cameras in views with their layer off.