How to solve a “duplicate items” error in the “Resources” parameter

Question

While working on my project, I got this error:

The item \"...\" was specified more than once in the \"Resources\" parameter. Duplicate items are not

Answer 1

I guess the item "..." is a form, then:

1. Remove the "..." form from recent solution (and save somewhere)
2. Recompile the project
3. Save the solution
4. Restart the solution
5. Add the "..." form
6. Recompile