When drawing a line, there was a small white box next to my cursor that would allow me to enter the length of the line I want. It would also sometimes have a degree option depending on the command I was using. It was there yesterday, and now it's gone. I searched the options but couldn't find what it was called. I'm not talking about the heads up display. I have the heads up display intentionally disabled.

Update: I just opened a different document and it's there, but for some reason it's disabled on the document I want it for, see pictures:

Update 2: I tried saving the document, it said error while saving, i couldn't draw any new lines, the command prompt wasn't working and I couldn't move lines. I exited the document and didn't save my changes, and reopened the document and now the little white box is back and also I can edit and save just fine. So was it just a bug?

How do I turn this back on?