Unfortunately, there is no such control. Perhaps you could style the items or subitems in a ListViewControl using some sort of Win32 API message, but there's no native way to do this in Plus! itself.
Actually, the Rich Edit Control doesn't support those tags. However, it does allow you to use PlusWnd::RichEdit_SetCharFormat to set the style of the current selection. This allows you to create a WYSIWYG editor with format buttons (although I have no idea how you would read the format out of the control afterwards).
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