Info message for when trace opacity is not supported

[bpostlethwaite]

Area charts for example do not support trace level opacity. See workspace2 info message.

[VeraZab]

I don't get it, isn't it even better that this styling option doesn't even show up in the editor, since that chart type doesn't have it?

[bpostlethwaite]

We have it in Chart Studio and that is our specification. Someone at some point put some thought into it and decided it was a good idea. I don't know who it was so I can't argue the point but that is why I am trying to replicate what we already have and not generate regressions.

[bpostlethwaite]

That doesn't mean all the ideas were good ideas but you should probably ask CP and AJ or Chels. Someone probably dealt with a confused customer at one point.

[alexcjohnson]

I suspect the message is there because it's often not obvious why the opacity option has disappeared - see the logic involved in https://github.com/plotly/plotly.js/blob/master/src/traces/scatter/clean_data.js - it can even be the properties of a different trace that invalidate opacity for this trace.

[alexcjohnson]

FWIW, scatter is currently the only trace type that has a module.cleanData method allowing traces to affect each other's attributes. I'll make a mental note that if we ever need to make another cleanData it may warrant another explanatory note to users!