Howdy, I spent a while chasing my tail today with some event handling code until I tried backtracking from SVN matplotlib back to 0.99.1 (the one in ubuntu 10.04) and the problem went away. I'm attaching a script that reproduces the problem with a full description in the docstring, reproduced here for completeness: This example wires two event handlers that both respond to clicks by printing event info identically. One is written as a standalone function, the other as a method of an object. - when run with MPL 0.99.1.1 (stock in ubuntu 10.04), both fire fine: amirbar[mplbrush]> python mpleventbug.py MPL version: 0.99.1.1 MPL: /usr/lib/pymodules/python2.6/matplotlib/__init__.py /usr/lib/pymodules/python2.6/matplotlib/backends/backend_gtk.py:621: DeprecationWarning: Use the new widget gtk.Tooltip self.tooltips = gtk.Tooltips() C1 - button=1, x=146, y=229, xdata=23.783488, ydata=0.846491 C2 - button=1, x=146, y=229, xdata=23.783488, ydata=0.846491 C1 - button=1, x=216, y=189, xdata=42.919628, ydata=0.671053 C2 - button=1, x=216, y=189, xdata=42.919628, ydata=0.671053 C1 - button=1, x=288, y=117, xdata=62.602515, ydata=0.355263 C2 - button=1, x=288, y=117, xdata=62.602515, ydata=0.355263 etc... - when run with matplotlib r8721, the one that is a method does not fire: amirbar[mplbrush]> python mpleventbug.py MPL version: 1.0.0 MPL: /home/fperez/usr/opt/lib/python2.6/site-packages/matplotlib/__init__.pyc C1 - button=1, x=150, y=170, xdata=24.876982, ydata=0.587719 C1 - button=1, x=169, y=160, xdata=30.071077, ydata=0.543860 C1 - button=1, x=187, y=135, xdata=34.991799, ydata=0.434211 C1 - button=1, x=210, y=120, xdata=41.279388, ydata=0.368421 ### This manifested itself in some more complex MPL code that had multiple events not working when run inside ipython, but working OK outside of ipython. Fortunately, the small self-contained example demonstrates the problem even with ipython not being in the picture at all (the runs above were from the command line), so I think there is an issue in MPL proper. Sorry that I can't dig deeper into the code right now to look for a fix... Timing note: EPD is planning a release in a few weeks, I don't know how close MPL is to a bugfix release in the 1.0.x series. I don't know what version of mpl EPD plans to use, but if event handling is really broken and a fix is feasible in the time available, it might be worth pushing it through. Cheers, f