Removing a unchecked map-feature does not get removed from map

[AliyanH]

To replicate:

• Go to this experiment

• Click "Add feature"

• Uncheck the "Empty" layer from layer control

• click "Remove feature"

• Recheck the "Empty" layer from layer control

• The layer still gets displayed despite the fact that the associated map-feature has been removed

          noticed another issue just now that I will work on, removing a map-feature when it is unchecked does not work (can be handled in a separate issue).
  

Originally posted by @AliyanH in #841 (comment)

[yhy0217]

Resolved in b472c21 and #873