Bug in the connected single range example

[yzaretskiy]

Problem Description
Connected single range example has a bug - left-hand side plot has all its points collapse onto the y-axis.

Reproduction Steps:
Run the linked example from the newly installed edm environment.

OS, Python version:
Ubuntu 16.04, Python 2.7, Chaco 4.7.1

[achabotl]

The demo worked in 4.6.1, Python 2 and 3 on macOS.

[yzaretskiy]

FWIW, it works on my Ubuntu 16.04 laptop when I revert to Chaco 4.6, but then I get the following warnings:

/home/yzaretskiy/.edm/envs/old-chaco/lib/python2.7/site-packages/chaco/array_data_source.py:123: FutureWarning: comparison to `None` will result in an elementwise object comparison in the future.
  self._data = newdata
/home/yzaretskiy/.edm/envs/old-chaco/lib/python2.7/site-packages/chaco/axis.py:498: FutureWarning: comparison to `None` will result in an elementwise object comparison in the future.
  for tickpos in mapped_tick_positions]))
/home/yzaretskiy/.edm/envs/old-chaco/lib/python2.7/site-packages/chaco/axis.py:499: FutureWarning: comparison to `None` will result in an elementwise object comparison in the future.
  self._tick_label_list = tick_list
/home/yzaretskiy/.edm/envs/old-chaco/lib/python2.7/site-packages/chaco/axis.py:500: FutureWarning: comparison to `None` will result in an elementwise object comparison in the future.
  self._tick_label_positions = self._tick_positions
/home/yzaretskiy/.edm/envs/old-chaco/lib/python2.7/site-packages/chaco/scatterplot.py:416: FutureWarning: comparison to `None` will result in an elementwise object comparison in the future.
  self._cached_selected_pts = points

[achabotl]

Those warnings were also reported in #251.

[rkern]

You can ignore the warnings. They were fixed by #350 which made it into the 4.7.0 release.

[cfarrow]

Note that the updated range is the one that gets messed up. In this case it's scatterplot. Swapping the assignment on line 42 results in the line plot getting messed up.

[rkern]

Found it: #394