Turning Off AutoCorrect Per Field
AutoCorrect can hurt more than it can help in Access forms. To turn it off at the application level (via Options... > Spelling) may not be the way to go as this could affect other Office applications---not to mention the preferences of your users.
Data Validation against ADP Forms
We should use the Other > Allow AutoCorrect property in the Properties dialog. This allows us to turn off AutoCorrect on a per-field basis.
After the data is entered into an ADP form, we should use T-SQL style expressions in the Data > Validation Rule property in the Properties... dialog. For example, to require a file name with an extension entered into a Text Box we have:
ALike '%_._%' Or Is Null
where I am still trying to figure out what "ALike" means. In any canse, we can see T-SQL-like syntax for LIKE expressions.