vispy/vispy — pull request #613 by drufat (2014-11-08 09:52:16+00:00)
Title: Fix mandelbrot zooming on mouse scroll.

Trying to scroll with the middle button of the mouse returns an error

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

With this patch the example works as expected.