void DoFont (int op, Bool recursive = TRUE)
See wxMediaEdit::DoFont (section 
). A snip
will get this message when its buffer gets the message, recusive
is TRUE, and the snip owns the caret. Override this method for
your own use.
Note that the snip's style variable is maintained automatically by the owning buffer. Override the DoFont method only to set styles of sub-items within the snip.