Sorry if this has been asked elsewhere, but I looked and though found some similar things about grouping layers in AGOL but could not find thread with this exact question as it relates to WAB.
Environment: ArcGIS Portal for Server (v10.3.1) and WABr Dev Edition (v2.1)
I have dozens of editable layers that are grouped into sub-folders in the MXD and in the published map services. The editable feature service ends up with all the layers ungrouped.
When you create a Web Map in Portal that includes both the map service (with the layers grouped) and the feature service (layers ungrouped), the web map layer list appears to recognize that the map service and feature service are related and so presents a single set of layers grouped in their original subfolders (screenshot below):
However, when the Web Map is brought into WAB, this all goes out the window and the editable feature service layers lose their groupings and are just listed out in the layer list as one big list with no folders, and then the non-editable map service with the sub-folders is shown a the bottom of the list (see screenshot below). ( It seems like ESRI has figured out how to make this work in the Portal Web Map viewer app, so not sure why the WAB Layer List does not behave this way!)
Question: Ideally I am looking for a way we could edit the Layer List widget so that the groupings would stay in place, and alternately, as possibly acceptable work around, I would be looking for how to have the non-editable map services show up a the top of the Operational layers and have the giant ungrouped list of editable feature services listed below them (this way the user doesn't have to scroll all the way through the giant list of editable layers just to get to the main map service).