I'm having an issue in which the cursor in Jupyter notebook v5.1.0 (running in a Version 61.0.3163.100 Chrome browser) disappears while I'm typing. The cursor will usually show up at the end of a line, but disappears again when navigating, as you can see in a screen recording. The navigating actually happens, I just can't tell where the cursor is at any given moment, unless it navigates to the end of a line.

This seems like it is likely a CodeMirror issue, but I haven't found an example sufficiently close to debug.