This is a weird bug that I have not been able to test, due to the unusual circumstances it appears. I also haven't been able to find mention of it elsewhere, so I'm stuck reporting it.

I was teaching a class where the projector screen was being used as a second monitor, and not duplicating the laptop screen. When I plot anything with matplotlib, it works just fine when it appears on the laptop screen. When I move the plot to the projector screen, the plot disappears... at about 75% on the projector screen, you can see the plot... but any more than that, the plot disappears. What's left is a blank window (i.e. what it looks like when you clear a plot). It has happened on every plot I've tried the past two weeks, at two different institutions.

To reproduce this bug, you'll need a second monitor. I've had overhead projectors only, but will try a second monitor shortly. I have seen the bug using matplotlib 2.0.0, python 2.7.13, and macOS Sierra 10.12.3. Any plot works, so plot(x) should do it, when you drag the plot onto the second monitor. Displaying a plot worked as expected previously, however, this is my first attempt displaying a plot using a second monitor with sierra. I installed matplotlib with macports, if that matters, and I'm using the MacOSX backend.

If I see the same effect on a second monitor (an actual monitor, not a projector), then I can test some variants. I have the opportunity today to try some other combinations of python and backend, and will update this issue accordingly.