Unordered lists in paragraphs and tables

Can someone explain why unordered lists aren't supported in CONCEPT or REFERENCE topics? (or why ULs appear in red, if they are supported?)

This is on a totally unmodified version of FM 10 (I also observed the same thing in FM 9). Here's how to recreate the problem:

Create a concept topic.
Add a body element.
Add a paragraph.
Note that in the element list, UL has a check mark next to it, indicating that it is a valid element to use in that context.
Add the UL.

Result: The text is displayed in red.

In FM 9, I hacked this display, by setting the font property for unsupported text from black to red. This disguised the problem in paragraphs contexts, but in unordered lists tables, this hack did not hide the problem.

I'm not an expert on EDDs, but the <P> element "contains" <UL>, so I don't know why the doc displays that text as unsupported.

Has anyone else seen this? Is this type of problem typical in structured Frame? I'm currently evaluating tools, and XMetal, ArbortText, and Oxygen seemed to be able to handle ULs just fine...