Summary: HTML links with title attributes lose focus if cursor moves even the slightest bit while the title box is displayed. This causes CSS dropdown menus to collapse. This bug does not happen on the first attempt after launch or restart, but does happen every time afterwords.
Below are two bare bones dropdown menu examples.*
The links in the left menu have title attributes; the links in the right menu do not have title attributes.
The title attribute should pop up after you hover/pause on a link (kind of like a tooltip). This happens correctly. but if you move or wiggle the cursor while the title is showing, then the link loses focus, and the menu collapses.
Try it with Firefox 3 on a Mac:
Hover on one of the left column drop down links, wait for title, then move/wiggle -- the menu item disappears, cuasing the menu to collapse. (The right column links have no title, so no problem.)
This bug does not occur in Firefox 3 or 2 for PC, nor does it occur in Opera, or Netscape on a PC. This bug does not occur on other Mac browsers either; Firefox 2, Camino 1.5, Safari 3.1.1 or Netscape Navigator 9 are all okay.
*Note: The Suckerfish CSS Dropdown Menu does not work in any IE for PC without Javascript help due to the :hover pseudo class. This example does not utilize the Javascript, and is designed to illustrate the bug in Firefox 3 for Mac only.