Dynamic text boxes, as the name implies, are designed to serve as containers for text from other sources (typically text loaded at run time). For that reason, you can't format individual text selections inside a dynamic text box. Any changes made via the Property Inspector are applied to all the text in the box. Additionally, dynamic text boxes have limited support for formatting applied to the source text.
In our exercise, the text was formatted in a standard static text box using only rudimentary formatting options such as Bold and Font Color. If you were to select the static text box and change its setting to Dynamic, all formatting would disappear. To maintain our formatting, we copy or cut the text from the static (formattable) text box to the clipboard, and then paste it into the dynamic text box.
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Dynamic text boxes support a small subset of HTML formatting tags in loaded text. Only the following tags are supported:
<a> anchor<a href=" "> hyperlink<b> bold<br> line break<font color> font color<font face> font<font size> font size<i> italic<img> image<li> list item<p> paragraph<u> underline