How to make HTML tooltips appear when hovering over a point in multiple axis?

Question

Although similar To this mouseover question, need solution using matplotlib mpld3 HTML tools. This code displays two plots, but only the second one has mouseover annotations. How to get tooltips on both plots?

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import mpld3
from mpld3 import plugins

# Define some CSS to control our custom labels
css = """
table
{
  border-collapse: collapse;
}
th
{
  color: #ffffff;
  background-color: #000000;
}
td
{
  background-color: #cccccc;
}
table, th, td
{
  font-family:Arial, Helvetica, sans-serif;
  border: 1px solid black;
  text-align: right;
}
"""

fig, ax1 = plt.subplots()
ax1.grid(True, alpha=0.3)

N = 100
r = range(N)
df1 = pd.DataFrame(index=r)
df2 = pd.DataFrame(index=r)

r2 = range(N/2)
df1['x'] = r
df1['y'] = r2 + list(reversed(r2))

df2['x'] = range(N)
df2['y'] = [ i*0.1 for i in list(reversed(r2))+r2 ]

labels1 = []
labels2 = []

for i in range(N):
    label1 = df1.ix[[i], :].T
    label2 = df2.ix[[i], :].T

    label1.columns = ['Row {0}'.format(i)]
    label2.columns = ['Row1 {0}'.format(i)]
    # .to_html() is unicode; so make leading 'u' go away with str()
    html1 = str(label1.to_html())
    html2 = str(label2.to_html())
    labels1.append(html1)
    labels2.append(html2)

points1 = ax1.plot(df1.x, df1.y, marker='o', ls='-', lw=4, color='b',
                 mec='k', alpha=.6, label='Line1')

ax2 = ax1.twinx()
ax2.patch.set_alpha(0)

points2 = ax2.plot(df2.x, df2.y, marker='o', ls='-', lw=4, color='r',
                 mec='k', alpha=.6, label='Line2')

ax1.set_xlabel('x')
ax1.set_ylabel('y1')
ax1.set_title('HTML tooltips', size=20)

ax2.set_ylabel('y2')
lns = points1 + points2

labs = [l.get_label() for l in lns]
plt.legend(lns, labs, loc=0)

tooltip1 = plugins.PointHTMLTooltip(points1[0], labels1,
                                   voffset=10, hoffset=10, css=css)

tooltip2 = plugins.PointHTMLTooltip(points2[0], labels2,
                                   voffset=10, hoffset=10, css=css)

plugins.connect(fig, tooltip1, tooltip2)

displayHTML(mpld3.fig_to_html(fig))