Unless they're deliberately off-center, it looks like the bars in bar charts are plotted a bit too far to the left relative to ticks, labels and grid lines (all of which seem to line up fine).

Here's an example that shows what I mean (you can see it in your browser, or else save to a PDF file and look at that):

df = DataFrame({'A' : [3] * 30, 'B' : range(30)}, index = range(30))
df.plot(kind='bar', stacked='True', grid=True)
draw()

2012/10/13 Richard Stanton <stan...@haas.berkeley.edu>

Had a look into the code. For an unstacked plot the bars have a width of
0.5, in case of stacked=True width is set to 0.75.
For both cases the xticks are set at the exact same positions. Result is
that grid is centered for an unstacked plot, but off-center in case of
stacked bar plot. Easy to fix.