Menus not closing correctly: 2 possible bugs

Bug #1: In a top-level menu bar, if you are on a menu item and move quickly so that the mouse is over the submenu indicator image of another item, the previous menu never closes and the new menu never opens.

Same behavior in FF and IE6/7. It is happening on this forum's menu, so the problem does not have anything to do with customization or configuration. Try moving quickly between "About" and "Demos", with the mouse ending up directly over the submenu indicator image.

Bug #2: Menus sometimes get stuck in the open position. Seems to me it happens when you mouse out of a top-level item quickly, traveling over a sibling item on your way out. Using this forum's menu as an example, hover over "Support" then quickly move up and to the left, briefly passing over "Purchase". The "Support" menu is left open and will stay open until you click the mouse or once again roll over a menu item.

Are these known issues? Can they be fixed?
Thanks in advance for any help you can offer!