If the issue is as the previous example demonstrated, good solutions don't really come to mind. Maybe you could try playing around modifying the Width of textbox and adding SpacerBox before it. No idea how well this would work in the long run.
Names Default To Here(1);
win = New Window("Example", V List Box(Align(right),
Spacer Box(Size(1400,0)),
fontobj = text = Text Box("This is bold text. This is italic text. This is underlined text. This is bold, italic, underlined text.")));
text << Set Width(500);
text << Justify Text("right");
text << setText(
"This is <b>bold</b> text. This is <i>italic</i> text. This is <u>underlined</u> text. This is <b><i><u>bold, italic, underlined</u></i></b> text."
);
wait(2);
text << markup;
-Jarmo