What algorithm does Windows 98 use to decide whether to show or hide menus?

Question

A comment on User Experience reminded me that Windows 98 keeps the All Programs submenus open when the mouse isn't on the menus, but if the mouse strays too far from the menus for long enough they all close.

I think that submenus also remain open if you move the mouse down to the next item and then across to the submenu if you do so quickly enough, but this may depend on a setting.

I have a suspicion that this behaved the same way as the Alt menus in Windows Forms programs.

How does Windows 98 determine when to open and close menus when accessed by the mouse?

Answer 1

I checked on Windows 98, and the behaviour I saw didn’t match your description (or my earlier answer).

Basically, whether you hold down the mouse button or not, menus stay open as long as you don’t click elsewhere or hit a key. Sub-menus open either immediately when you click on their parent menu entry, or after a short delay if the mouse pointer hovers over their parent menu entry. They stay open until you move the mouse pointer over another menu entry, although you do get a slight delay to facilitate diagonal movement (possibly over another menu entry, for a brief instant).

The big difference compared with Windows 3 is that the mouse pointer moves the menu selection on its own, without needing mouse clicks. In Windows 3, you could open a sub-menu, and the selected entry would stay on the first (selectable) item until you clicked on another entry, or dragged the mouse with the button depressed; in Windows 98, simply moving the mouse pointer moves the menu selection and opens sub-menus.