As far as I remember Fireworks has always been goofy with that, compared to
Illustrator at least. You can type the first letter of the font you want, say
if I wanted Helvetica, I could type "H" to get close. If I typed H-E, it would
move me to H then skip to E in the list. You might be having trouble if
Fireworks has memorized some of your recent fonts at the top of the list.

Again if you wanted Helvetica and pressed "H" to get there, but you had
recently used Haettenschweiler, Fireworks would take you to the top of the list
and highlight Haettenschweiler. In this example, if you pressed H again you'd
skip to the next font, hopefully past the "recent fonts" at the top, and to the
proper H section further down.

Being able to type out the entire name of the font to jump to it would be an
awesome addition to Fireworks. Perhaps we can chase Adobe down with spears and
torches or something.