Hmm. This doesn't seem to work for me. The below script
nw = New Window("Example of markup in text box",
Text Box("<b>This is in bold but wraps awkwardly</b>", << Markup, << Set Wrap(1200)),
Text Box("", << Set Wrap(1200)),
Text Box("<b>This is not in bold but wraps correctly</b>", << Set Wrap(1200))
);
Gives me the following
Additionally, not calling it a message is misleading (this part is a complaint, not a problem). Internally, JMP refers to it as a message. For example, if I type some garbage like "<< Set Milk" to a text box, I get the following in the log:
The display box 'TextBox' does not recognize the message 'Set Milk'; perhaps you mean one of these: <<Save HTML <<Get XML <<Set Tip <<Set Wrap… <<Set Text <<Get Tip <<SetNLines <<Set Width, etc.