Can't plot with GTKCairo or GTKAgg backends any more

[John Pye]

On a new clean 17.04 system with only standard packages installed, I can't use GTKAgg or GTKCairo backends with Matplotlib any more. This breaks my Python2 + GTK2 GUI, since I need to embed GTK-based plots.

Note clear why the problem is arising, but this following shows the problem:

$ ipython
import matplotlib; matplotlib.use("GTKCairo"); import pylab; pylab.plot([1,2],[3,4]);pylab.show()

See also:
https://stackoverflow.com/questions/14346090/importerror-no-module-named-backend-gdk

[John Pye (jdpipe)]

Not a bug. I had a non-Ubuntu copy of matplotlib in ~.local/lib/python2.7 which was causing this error.