Is there any way to programmatically recognize individual character formats
in a comment for superscript, subscript, or double underline?

ActiveCell.Comment.Shape.TextFrame.Characters(i, 1).Font.Superscript
and
ActiveCell.Comment.Shape.TextFrame.Characters(i, 1).Font.Subscript
both exist, but do not appear to be maintained by Excel, since they are
always Null.

ActiveCell.Comment.Shape.TextFrame.Characters(i, 1).Font.Underline
is maintained by Excel, but as a Boolean (which therefore ignores double
underline), unlike
ActiveCell.Comment.Shape.TextFrame.Characters.Font .Underline
which contains values like xlUnderlineStyleNone, xlUnderlineStyleSingle, and
xlUnderlineStyleDouble

Jerry