Numbers Chart - can't get out of "Edit Data References"

I've got an X-Y Scatter graph in Numbers. I'd like to edit the data - and although I am able to edit the data to my liking I find I CAN'T EXIT the Edit Data References mode. I tried the escape key - that doesn't exit out of this mode. I tried randomly clicking other things - didn't work.

The only way I know how to get out of Edit Data References mode is to quit Numbers and restart.

Anyone else have this issue? Is there a way to exit out of Edit Data References when modifying data of a chart?