mesh coloring: intensity doesn't clear

[VeraZab]

intensity persists even if set to null and not present in _fullData.
http://codepen.io/veraz/pen/LZZJjv

[mdtusz]

You just need to wrap the [null] in another set of square brackets to clear the values.

If my suspicion is correct, the null is ignored as if there is no restyle for that trace index - this allows for multiple traces to be updated at once, while still leaving some untouched. E.g.

Plotly.restyle('chart', {intensity: [null, [0, 1, 2, 3], [null]]} , 0 );

[VeraZab]

You're right, it works with [[null]]
But many of the other restyle properties are clearable with just null, should we be using [[null]] everywhere?

[etpinard]

@VeraZab that's because intensity is itself an array attribute.

Very confusingly, the outer arrays in restyle correspond to the traces to update, while the inner arrays correspond to the update values.

In more details: see #167 (comment)