I have long had a problem with SVG matplotlib output in the notebook. Intermittently, the plot will extend outside of the axes, as exemplified in this screenshot:

Basically, everything below the horizontal axis should be hidden. Most of the time, it is properly hidden -- e.g., when the plot is first made, or when I collapse and expand the output area. But then sometimes, it'll go buggy like this. I can't reproduce this consistently, but it seems to happen most often when I make a plot in another cell.

That stuff that's usually hidden evidently does correspond to actual data; when I plot again with xlim(xmin=1e-18), the data does show up just like that, except that it is correctly based at 1e-18. So it's evidently really in the SVG.

I'm wondering if this is related to #1881 and #2647, but none of the descriptions of problems there were specific enough. Is this expected badness in the matplotlib output?

I've had this problem for a long time (years?), but I can verify that it exists currently in IPython 3.0.0. I'm seeing it in up-to-date Chrome and Safari on up-to-date OS X, using an up-to-date anaconda installation (python 2.7). Here are the IPython details:

{'commit_hash': u'f75fda4',
'commit_source': 'installation',
'default_encoding': 'UTF-8',
'ipython_path': ..../anaconda/lib/python2.7/site-packages/IPython',
'ipython_version': '3.0.0',
'os_name': 'posix',
'platform': 'Darwin-14.1.0-x86_64-i386-64bit',
'sys_executable': '/Users/boyle/.continuum/anaconda/bin/python',
'sys_platform': 'darwin',
'sys_version': '2.7.9 |Continuum Analytics, Inc.| (default, Dec 15 2014, 10:37:34) \n[GCC 4.2.1 (Apple Inc. build 5577)]'}