### Bug report **Bug summary** When using Matplotlib 1.5.3 in iPython with the TkAgg backend, control is not returned to iPython after showing a plot and closing the window. **Code for reproduction** ```python In [1]: import matplotlib as mpl In [2]: mpl.use('TkAgg') In [3]: import matplotlib.pyplot as plt In [4]: plt.plot([0, 1]) Out[4]: [<matplotlib.lines.Line2D at 0x7fb09f2a0350>] In [5]: plt.show() ``` **Actual outcome** Closing the window does not return control to iPython **Matplotlib version** * Operating System: Linux * Matplotlib Version: 1.5.3 * Python Version: 2.7 * Other Libraries: iPython 4.1.2, but it happens with other versions too. Installed via conda via conda-forge channel The issue doesn't occur in 2.0. Are there likely to be any more 1.5 point releases?