Basically we got rid of the two menu system and replaced it with a single menu system. With only one menu, the whole screen would be available to modules. Each module is entirely free to respond to all button presses except the STAR button, which is used to cycle between modules. You can use the up/down buttons to cycle between different modules in the menu!
To have a module displayed in the menu, the module should call menu_add_entry() (ezchronos.h). A good place to call this function is in the module's _init() function.
Old menu code had a very bad way to handle the edit mode. Edit mode is when you are, for example, displaying the alarm and want to change values of the alarm using the chronos buttons. Now, to enter edit mode, you only have to call menu_editmode_start() (ezchronos.h).
For more information about how to use these functions, see modules/clock.c or modules/alarm.c