Out of interest, I (unusually for me) used A2016 the other day to build a database and noticed that Shift-F2 to expand a text box showed teeny text - The font was set to size 1 by default. Changing it to a sensible size changed it for all shift-F2 operations. I did include some rich text fields (which is why I wanted A2016). I don't know whether having rich-text fields makes a difference. I didn't have any data-sheets, just continuous forms.
Perhaps this is all part of the same issue.
I would definitely review the form settings for bg and fg, in case it is using some crazy windows settings.