Green bar in notebook
It happens somewhat often, with different programs, that I click shift-enter to run a long calculation in Sage, and at some point later notice that the green bar is gone, but now that skinny red bar is there, as if it had never been run. And, if I try to run something else, even something that takes a millisecond, it sits there with the green bar. My thought is that the original long calculation is still running. Do you think my estimation is correct? If so, is this a known issue? Is there a way to fix it?