Compare
http://matplotlib.org/devdocs/examples/scales/scales.html (~2.0b4)
and
http://matplotlib.org/examples/scales/scales.html (1.5.3)
no tick labels are drawn on the negative side of the symlog plot in 2.0b4, unlike e.g. 1.5.3 which works fine.
Bisected back to PR #5161, but some commits within the PR don't run so I can't do better.