Steps to reproduce:

1. Create dashboard.
2. Add Map navigation tree widget. 
3. Add Map widget with "Source type - map navigation tree". Connect it to map navigation tree widget created before. 
4. Copy Map navigation tree widget.
5. Paste widget in same dashboard.
6. Now, open Map widget edit form.

Result:
Console error appears.

Expected:
No console error. No duplicated option value for map navigation tree.