If you disabled a series in a multi-bar chart (either horizontal or
vertical), you would get incorrect tooltips. This was caused by the
fact that we only set the mouseover on the `enter()` elements, which
meant that nothing was being set when the chart was updated due to the
hiding. This caused us to close over the original value of the data
The fix is to set the mouseover on the entire selection, which updates
it every time the chart is updated. This also contains a small fix to
the horizontal multi-bar chart to have a more descriptive tooltip.
Horizontal bar charts didn't update correctly - the data that the width
was calculated by was bound to previous values.
The fix was to use `select()` instead of `selectAll` on the bars
themselves (since there is only a single `rect` element in each). This
is because `selectAll` doesn't propagate data bindings, per the
following links:
https://groups.google.com/forum/?fromgroups#!topic/d3-js/PUansS150J0https://groups.google.com/forum/?fromgroups#!topic/d3-js/272vChmijIw
It works the first time because of the `.enter()` definition which will
cause data to propagate, as mentioned in the above threads.
Luke Steensen
Itay Neeman
Bob Monteverde