Why does Framemaker DropDownCaption (dynamic html effects) not work in table cell?

Using FrameMaker 12 I created a document with two paragraphs of text.

Then I assigned  DropDownCaption to first line of text.

Next assigned DropDownBody to the second paragraph (exactly as described in Help).

When I output this using Publish -> Web help it works as it should; that is, you click first line and the hidden paragraph that follows appears.

Now, in my source I add a table and assign exactly as above DropDownCaption and DropDownBody to same two paragraphs of text in one of the table cells.

When I update the Web help, the drop down text in table does not work. Instead both Caption and Body show; when the Caption is clicked the heading 'jumps' a little.

(Have also tried from Robohelp importing the framemaker document but same problem.)

I have not seen any postings anywhere with this problem, most likely because few people are using this function in a table.

Appreciate any help.