I have created two Map Image Layers in our enterprise (Portal) system. The first has all the basic map layers that we would use in any map and the other has just has our parcel feature.
Next, I build a map in ArcGIS Online and added these Image Layer using their URLs. I put the Basic Map Layer on top and the Parcel Map Layer under it.
Then I built an Experience that uses this ArcGIS Online map. I add a Feature Info Widget and try to get it to display parcel information when I select a parcel in the map. The only thing I can select is features from the Basic Map Layer because it is on top. For the parcel selection to work, I had to change the map and make the parcel layer the first in the list or on top. It looks better on the bottom, but this is how it works. With this change, it would select the parcel and populate the Feature Info Widget.
It would be great if there was a toggle that would allow a person to say this layer is not selectable or have some kind of control over what layers are being selected for that widget and ignore all the others.
I hope this suggestion helps. There might be a way to control selection, but I am not aware of it. If someone has any suggestions, I would love to hear them.
To see the final app - https://experience.arcgis.com/experience/72bc7bb60fc54248beb30172d7e5f9f5#data_s=id%3AdataSource_1-18f839b400b-layer-65-103%3A22644