Issue 1:
With the current master, I am finding that interactivity can break in case of errors.

This is one example:

>>> import matplotlib
>>> matplotlib.use("tkagg")
>>> from pylab import *
>>> figure()
<matplotlib.figure.Figure object at 0x103b03150>
>>> line, = plot([1,2,3])
>>> line
<matplotlib.lines.Line2D object at 0x108f81350>
>>> line.set_dashes
<bound method Line2D.set_dashes of <matplotlib.lines.Line2D object at 0x108f81350>>
>>> line.set_dashes('--') # incorrect usage of set_dashes
>>> Exception in Tkinter callback
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk/Tkinter.py", line 1536, in __call__
return self.func(*args)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk/Tkinter.py", line 587, in callit
func(*args)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/backends/backend_tkagg.py", line 370, in idle_draw
self.draw()
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/backends/backend_tkagg.py", line 354, in draw
FigureCanvasAgg.draw(self)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/backends/backend_agg.py", line 471, in draw
self.figure.draw(self.renderer)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/artist.py", line 60, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/figure.py", line 1119, in draw
func(*args)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/artist.py", line 60, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/axes/_base.py", line 2169, in draw
a.draw(renderer)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/artist.py", line 60, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/lines.py", line 741, in draw
drawFunc(renderer, gc, tpath, affine.frozen())
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/lines.py", line 1154, in _draw_lines
self._lineFunc(renderer, gc, path, trans)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/lines.py", line 1201, in _draw_dashed
renderer.draw_path(gc, path, trans)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/backends/backend_agg.py", line 166, in draw_path
self._renderer.draw_path(gc, path, transform, rgbFace)
TypeError: a float is required

>>> plot([1,2,4])
# nothing happens

>>> cla()
# nothing happens

Resizing the figure restores interactivity.

Issue 2:
Bug report

Bug summary

Setting axis ticks in a small log scale produces duplicate tick labels.

Code for reproduction

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
s = 10
ax.axis([s, 100, 10, 100])
ax.loglog([20, 30], [30, 40])
from matplotlib.ticker import ScalarFormatter
for axis in [ax.xaxis, ax.yaxis]:
axis.set_major_formatter(ScalarFormatter())

ax.set_xticks([20, 55])
ax.set_yticks([20, 55])
plt.show()

Actual outcome

change code a little bit

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
s = 9
ax.axis([s, 100, 10, 100])
ax.loglog([20, 30], [30, 40])
from matplotlib.ticker import ScalarFormatter
for axis in [ax.xaxis, ax.yaxis]:
axis.set_major_formatter(ScalarFormatter())
ax.set_xticks([20, 55])
ax.set_yticks([20, 55])
plt.show()

Expected outcome

Matplotlib version

Operating system: Ubuntu 16.04

Matplotlib version: 2.2.2

Matplotlib backend: Qt5Agg

Python version: 3.6