My Python script executes in a new dedicated Python console in Spyder, where I have configured Spyder's run options to allow interaction with the dedicated Python console after execution. After execution, my script leaves multiple figure windows open and minimized. I do the following:

1. Click on the last figure window to bring it into focus.
2. Click on the icon "Edit curves line and axis parameters"
3. Change the X-axis max parameter
4. Click Apply
5. Click OK
   matplotlib minimizes the window I just edited, then freezes. When I click on another figure window, the figure window I just edited pops up instead. When I try to edit the axis parameter of the same figure again, I hear the Windows error beep sound.

I use 64-bit WinPython on Windows 8.1. WinPython uses wheels from http://www.lfd.uci.edu/~gohlke/pythonlibs/#matplotlib

I have observed this problem in:
a) Python 3.5.2, Spyder 3.0.2, matplotlib 1.5.3, Qt 5.7.0, PyQt5 5.7
b) Python 3.5.2, Spyder 3.1.0dev, matplotlib 2.0.0rc2, Qt 5.7.0, PyQt5 5.7
c) Python 3.4.4, Spyder 3.0.2, matplotlib 1.5.3, Qt 5.5.1, PyQtt 5.5.1

The problem is a regression, because my same script works fine in:
d) Python 3.5.2, Spyder 2.3.9, matplotlib 1.5.3, Qt 4.8.7, PyQt4 4.11.4
e) Python 3.5.2, Spyder 3.1.0dev, matplotlib 2.0.0rc2, Qt 4.8.7, PyQt4 4.11.4