easy-menu-precalculate-equivalent-keybindings is a variable defined in `easymenu.el'.
Its value is

  • This variable is obsolete since 23.1.

Determine when equivalent key bindings are computed for easy-menu menus.
It can take some time to calculate the equivalent key bindings that are shown
in a menu. If the variable is on, then this calculation gives a (maybe
noticeable) delay when a mode is first entered. If the variable is off, then
this delay will come when a menu is displayed the first time. If you never use
menus, turn this variable off, otherwise it is probably better to keep it on.