Text style is hit or miss for me

[Roger Eller]

 I am attempting to add formatting buttons above a field.  If the text is
typed into the field, my formatting buttons work as expected.  When a user
pastes text from another application, my formatting works sometimes, but
not always.

Below is what I use in my Bold button, and Italic button. I want to keep
the style that is already applied, and add an additional style, for
example, if the selection is already bold, I want it to stay bold but add
italics.

set the textStyle of the selectedChunk to (the textStyle of the
selectedChunk) & "," & "bold"

set the textStyle of the selectedChunk to (the textStyle of the
selectedChunk) & "," & "italic"
How do you guys do formatting buttons?

~Roger