When the nav window is hidden, units can sometimes disappear when they are in the range of where the nav window would be. Interestingly, units "above" where the nav window would be can still be visible.
[ ] Units should be visible and drawn if their y-range is in the screen at all.
The critical factor is the nav window off, which can't really be avoided.
Places to test:
Key behaviors are:
Test with all combinations of the following: