The designer does not work in Visual studio. Why?

Question

visual studio

Here is a joke showing:

Answer 1

This means that the form was edited manually, and somewhere there are extra characters or there is no closing bracket. Re-create the form.

Answer 2

It is better not to climb into the designer with your hands. Or, if you climb - clearly know what and why you are doing.
You have two options:
- look for an error in the designer;
- create a new form and transfer the logic (code).