Using rgba colors in colorscales for parcoords plots results in all black lines.

[SaschaJust]

Observed

The parcoords plot behaves differently for rgba color strings than others (rgb, hex, string) when used in a colorscale. When using rgba all lines are rendered black. When using a different color string type in the colorscale, lines are drawn in their respective colors.

Expected

The type of the color string should not impact the functionality of the colors in the trace.

Reproduction

This is the definition of the colorscale used in the example.

Broken

Codepen: https://codepen.io/SaschaJust/pen/JVqoaL

"colorscale": [
            [
                0,
                "rgba(255,0,0,1)"
            ],
            [
                1,
                "rgba(0,0,255,1)"
            ]
        ]

Working

If you replace the rgba strings by their rgb counterparts, the plot renders as expected.

https://codepen.io/SaschaJust/pen/xeNGOy

"colorscale": [
            [
                0,
                "rgb(255,0,0)"
            ],
            [
                1,
                "rgb(0,0,255)"
            ]
        ]

Notice that the colorbar works fine in both cases.

[etpinard]

Thanks for the report!

Related: #1356