Rich text fields in Access 2007 are severely limited. They support a minimal
subset of html tags, mostly font and paragraph formatting. They do not
support sub and superscripts. Worse than just not displaying the text
correctly in a textbox with TextFormat set to Rich Text, Access sometimes
silently removes the unsupported tags when you edit that data. I resorted to
only allowing data edits with text boxes set to plain text format, so the
user has to edit the tags manually. Displaying the data in a form works
correctly in a web browser control, which supports all html tags, but that
control does not have a CanGrow property so it's not of much use in reports.
In that case I use a rich text box for the report, and unsupported html tags
are ignored.
I had assumed that Access' rich text fields would be more useful, and was
disappointed to discover these limitations after starting a project that
uses html for rich text.