Lost the Winform graphic form editor

Question

Hi,
Not for the first time, I made a slight mistake, and lost my Winform graphic editor (like Form1.cs[Design]).
I get instead a blank new Form1.
I can run my program and get the form with all its controls running, but I can not display the original form designer screen.
The problem seem to have started when I mistakenly defined a new form Form1.
I have tried to rebuild the controls with the new form, but naturally it won't let me use the same names, while new names serve no purpose.
The fact that I can run the program indicates that the form information is somewhere in the project (probably in the , but I can not edit it.
Is there a way to rebuild the graphic form designer ?
Is there a way to avoid such errors in the future?  (I always wondered why MS did not enable the saving of all versions while editing and before closing a project??)