Spatial Map Series: Field to select a "layer visibility and symbology" bookmark
Some feature layers need more than a single way of visualizing.
Raster layers can have different symbologies that are easy to switch to.
Adding this option for feature layers is the first step to being able to create powerful map series.
The second step is the ability to save layer visibility AND layer symbology (and label), in a "layer visibility bookmark" (or "theme") that also remembers the symbology.
Now a true map series is possible, enabling different symbology and different layers to be used, depending on the map. The index layer can be all of same location with a different layer visibility and symbology.
What this fixes:
Enabling full control of map extent, styling and layer visibility.
In 3.2 there are themed map series, that require radio button layer groupings. However, this does now work for different map extents.
Moreover, whenever a layer needs to be present in multiple "themes" (radio button groups), but not all of them, then duplicating layers becomes necessary, and a change in symbology in duplicate layers if very painful to do. The content panel quickly becomes extremely cluttered.