Remote default style is mishandled by MapML module

[prushforth]

The behaviour of the remote default style is broken compared with the local default style.

To obtain a correct round-robin list of style links in the layer control, you need each of the styles to "know about" all the other styles available for the layer. The current style is tagged with rel="self style", and that is the default style from the preview. So, for the states layer for example, you set up a Default style in the styles dropdown of "population":

and you make the default style also one of the alternate style options in the style selector as shown.

These styles then become selectable in the MapML preview layer control, and when you switch styles via that mechanism, the styles in the new layer are maintained (the new layer "knows about" the other styles).

Default style shown (before switching to another style):

Alternate style selected (after switching from population):

In contrast, a remote cascaded WMS, the default style is identified, and selected:

The default style is indeed selected in the preview before making an alternate selection (7 alternate styles):

However after making an alternate selection, the default style is no longer "known to" (at all) the alternate (only 6 alternate styles known):