1. Stop at a breakpoint.
   I stopped after the line:

   int i = 1;
   

2. Add a new expression evaluator.
   I added "i".
   The value of the expression evaluator will be displayed in the Locals and Expressions view.
3. Double-click the expression evaluator there, change it and press Enter.
   I changed it to "(char) i".
   The expression evaluator will be left unchanged and a new one will be added.

I had expected that the existing expression evaluator will be changed.