This great little plugin worked perfectly until I installed sh404SEF. After a great deal of troubleshooting, I found the problem could be resolved by turning off both "show section" and "show category" within the configuration rules for sh404SEF. Adding FW Tooltips to be skipped by the SEF component didn't work either.
It would also be nice if this plugin accepted longer tooltips. The limit appears to be 256 characters, including HTML markup.
This is the only Tooltip plugin I found that works with a component to manage the definitions. I would switch to something like YOOtooltip, but it does not have the functionality of FW Tooltips in this regard.