What you want to do is popup a topic, not just text. Create a topic file with the information and appearance you want. In the main topic, insert a hyperlink, select the topic to popup, then set the target to Popup Window. Depending on how much content is in that topic being popped up, you might want to modify the width and height dimensions of the a.popup styles in the stylesheet so that the popup window is wider and taller. Once you've modified the styles, edit the hyperlink the main topic to include a reference to the "Popup" class style.
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