Add multi-select to Collector for ArcGIS dropdowns

[JohnGillham]

The Collector for ArcGIS app supports dropdowns through the use of domains, but currently only allows for a standard single-selection dropdown in the app. Some data collection efforts  require the user to choose multiple items to add to the record's field (as comma separated items within a single field). It would be very useful to allow for a way to allow either a multi-select dropdown or a checkbox list for certain data fields displayed in the Collector app.

[משהגוטמן]

I see this issue was not dealt with yet in the GIS online.
I have tried to go around the problem by having two fields - a filed holding the selection list and a field collecting the data for each selection.
The collecting filed is claculated to add new selections. Though, I have only suceeded selecting one item on each editing (so for selecting 3 items, the point should be edited and saved 3 times).
I am trying to find the way that each change of selection will add the new selection without the need to save and exit the editing.