I have a specific situation with slideToggle that creates a flicker in Firefox.

The situation was when the expanding element goes longer than the page and a vertical scrollbar appears in Firefox.

If you scroll down to read all of the text in the expanding element and then click on the trigger to close the element, Firefox would flash for a second and then the page readjusts and returns to its position before the expanded element was expanded. I have tried adding ‘return false;’ to no avail.

Here's a test page where you can see the effect in FF when you click to close the last item (Herbal Teas): http://pollak-labs.com/clients/birthyourself/?page_id=21