Enable WMS layer for Screening tool as selectable layer

[TijsLips]

This idea is related to the "Screening" widget, available in ArcGis Online Web Mapping Applications. I would like to be able to select a WMS feature to buffer around. At this point, I can select the WMS layer in the "Select draw tool selectable layers"-block and enable the "Draw Tools" section - but the widget will not work.

It would be great of I could select a WMS feature on the map and create a buffer around it.

[MikeSlattery]

This may be related but it would be very useful to allow the Screening widget to select polygons from one layer as the shape to use for screening another layer.    We would like to create persistent shapes on the map and have them as options instead of freehand drawing.   Thank you!