Delete all records will delete all records of the table specified in "show Records from" in layout setup of the layout that is current at the time you select this menu option.
Question marks indicate that FileMaker is unable to display the data in the field. Since you see the correct date when you click into the field, try resizing the field to make it wider. Perhaps the currently specified date format is wider than will fit in the field. (These are fields of type date, not text, correct?)
I realized what it was and your second presumption was closer. It wasn't the width or height of the field. They were dates, but I had changed the formatting from "as entered", for example, "11/23/12" to the "November, 23 2012" format and I suppose that it didn't recognize that as a legit date when it came back in, so I went back to the original layout and changed the format back to "as entered", reformatted, then it was fine.