[Maps] Visibility issue with WMS layers

[jsanz]

Kibana version:
7.9

Elasticsearch version:
7.9

Server OS version:
Ubuntu 20.04

Browser version:
Version 1.12.112 Chromium: 84.0.4147.125 (Official Build) (64-bit)

Browser OS version:
Ubuntu 20.04

Original install method:
Official docker image

Description of the problem including expected versus actual behavior:

Adding a WMS layer makes other layers to not show properly.

Steps to reproduce:

1. Add flight data
2. Create new map
3. Add WMS layer, for example:
   • http://www.ign.es/wms-inspire/ign-base
   • Layer: callejero gris
   • Attribution text & link: anything
4. Add flight documents (blended layer is OK)
5. Hide the WMS layer
6. Save and come back
7. Document layer is hidden
8. Show WMS layer, documents layer is visible also

Issue reported on our community forums

[elasticmachine]

Pinging @elastic/kibana-gis (Team:Geo)

[nreese]

Looks like this is a regression caused by #69444. That PR changed the sort algorithm for layers.

The layer is there, it is just underneath the base map layer so you can not see it. If you hide the basemap layer, then you can see it.