imshow hides a part of the axes

Hi,

When using an imshow command whose extent is larger than the axes
limits, the axes are partially hidden by the image. That is, one half
of the axis line is hidden and the other appears fine. I made sure
that ax.set_axisbelow is False.

I attached a screenshot of the png file, look at the top axis.

Using version 0.86.2

Thanks,

David