Description of problem:
I have for years used 'ipython -pylab' to interactively plot using matplotlib. Recently, however, interactive plotting no longer works. I cannot say the exact combination of ipython/matplotlib versions of when this broke, but it was in the last three or four months.

Version-Release number of selected component (if applicable):

$ rpm -q ipython
ipython-0.10.1-3.fc13.noarch
$ rpm -q python-matplotlib
python-matplotlib-0.99.1.2-4.fc13.x86_64

This combination of ipython and matlabplot is the latest available on F13 and it shows the problem. I am not sure about any other versions or combinations of versions.

How reproducible:

$ ipython -pylab

  In [1]: import pylab

  In [2]: pylab.plot([0,1],[1,0])
  Out[2]: [<matplotlib.lines.Line2D object at 0x255d390>]

Historically after running this command a matplotlib plot would have popped up, but it no longer does. So if you then run pylab.show(), it will pop up, but it blocks and is not interactive as before. Then when you close the plot that popped up, it continues to block. It is hung. After waiting a long time, I hit Ctrl-C, and I get the following message:

In [3]: pylab.show()
^CERROR: An unexpected error occurred while tokenizing input
The following traceback may be corrupted or invalid
The error message is: ('EOF in multi-line statement', (332, 0))

---------------------------------------------------------------------------
KeyboardInterrupt                         Traceback (most recent call last)

/home/lane/<ipython console> in <module>()

/usr/lib64/python2.6/site-packages/matplotlib/backends/backend_gtk.pyc in show(mainloop)
     76     if mainloop and gtk.main_level() == 0 and \
     77                             len(Gcf.get_all_fig_managers())>0:
---> 78         gtk.main()
     79 
     80 def new_figure_manager(num, *args, **kwargs):

KeyboardInterrupt: 

In [4]: