I have the problem that after importing seaborn, lines with markers do not show markers anymore.

The following will first output a plot with a blue line and three markers (the two on the ends are barely visible, but the one in the middle is clearly there), but after importing seaborn, the markers are not anymore visible.

import matplotlib.pyplot as plt
%matplotlib inline
plt.plot([1,2,3], marker="o")
# marker visible on the blue line
# -- next cell
import seaborn as sns
plt.plot([1,2,3], marker="o")
# No marker shown

I tracked that down to this diff in mpl.rcParams

 lines.marker: None
-lines.markeredgewidth: 0.5
-lines.markersize: 6.0
-lines.solid_capstyle: projecting
+lines.markeredgewidth: 0.0
+lines.markersize: 7.0
+lines.solid_capstyle: round
 lines.solid_joinstyle: round

Setting lines.markeredgewidth to 1 will again show the marker.

mpl.rcParams["lines.markeredgewidth"] = 1
plt.plot([1,2,3], marker="o")
# marker shown again

I tried to reproduce it on try.jupyter.org with the python2 kernel, but couldn't, despite the same mpl version (matplotlib.__version__ == '1.4.3'). My system is py2.7, win7, conda (matplotlib + seaborn updated to latest, but pandas/numpy a little older due to "never change a running simulation"...).