That requires the hover widget plugin by Andreas Hahn. His site is somewhere, I don't have the link handy at the moment.
You can get the widget off of the wiki reference wiki here http://inmysocks.tiddlyspot.com/#%24%3A%2Fplugins%2Fahahn%2FhoverWidget -- You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/tiddlywiki. To view this discussion on the web visit https://groups.google.com/d/msgid/tiddlywiki/d470dc9d-7aee-4cbf-8747-adfd6ed8c485%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.

