I can't create an autocorrect to replace two spaces after
a period by only one space as it should be now. As soon as
I press the spacebar, the Add button of the AutoCorrect
dialog boxes becomes unavailable.

I know about the grammar settings that you can configure
regarding this but it simply adds the green wavy underline.

The alternative I found is to create a macro that does
what I want and I run it everytime I finish a document.

Does anyone know of a way to add this autocorrect?