Gary,
LABEL, TEXTEDIT with textFormat="html" are intended to display a subset of html, see the important notes here
http://4js.com/online_documentation/fjs-fgl-manual-html/#fgl-topics/r_fgl_presentation_styles_label_style_attributes.html so I suspect WEBCOMPONENT is going to be what you need to display any HTML of the email bodies.
I'm guessing you'd have
HBOX
SCROLLGRID or TABLE
{
email fields, date, from, to etc
}
END
GRID
{
web component field to display body of currently selected row on left hand side via BEFORE ROW
}
END
END
END
Reuben