matplotlib/matplotlib — pull request #2986 by efiring (2014-04-18 21:53:01+00:00)
Title: ENH: allow changing the Axes sort order for event handling

Previously, when a second axes is created using twinx, for example,
that axes catches all events; cursor position is shown based on
that axes, etc. The Figure.swap_axes_order() method allows one to
exchange the sorting indices of the two axes, so that the first
axes can process events instead of the second one.