How do you remove this random line from a graph?

[#1]

When I am in graph builder working on a line graph, sometimes a random black line appears and I am not sure where it is coming from or what it's for. How do I get rid of it?

[Note: Variables in the column box are redacted out in this post, but there are items there.]  

[#2]

It looks like a ref line. Double-click the axis and see what's in the axis settings.

A Ref line on the X axis.The real question might be how did it get there without using the dialog? Are you running this from a script? Is it always at the same value? What version of JMP? Mac or Win?

Edit: does the Time variable in the data table have any special properties? Possibly there is a way to add the ref line there. Look at the small icons near its name in the left panel of the data table, click on the one you don't recognize. (I'm guessing a bit...)

Edit 2: yes, maybe this?

The * is for properties, and the axis dialog is one of the possibilities.

[#3]

And just saw the Mac label on this too. Probably not going to be a mac specific issue.