Donut/Pie issue with shown active arcs with some category

[panthony]

Not sure if it's the same issue as #1793 but with the following configuration:

var chart = c3.generate({
    data: {
        columns: [
            ['> 0', 1],
            ['== 0', 2],
            ['< 0', 3]
        ],
        type : 'donut',
        order: null,
        onclick: function (d) { console.log('click', d); },
        onmouseover: function (d) { console.log('over', d); }
    },
    color: {
      pattern: ['green', 'grey', 'red']
    }
});

If I hover the arc corresponding to > 0, the arc for < 0 is also shown as active.

Works fine if categories are 'a', 'b' or 'c' ...

The over/click events and the tooltip are ok.

See https://jsfiddle.net/mcd6ucge/131/

[panthony]

It's because the active/hover state is based on the css class of the arc.

This class is generated by normalizing the category name.

The categories > 0 and < 0 are both normalized as c4-arcs--0 (> and < are replaced by -).

[panthony]

Duplicate of #1687