ZoomText doesn't read context menus initially. Only after a sub menu
of the context menu or a sub menu of the menu bar has been opened,
context menus are read.

As found out by Oliver Braun the reason for this behaviour is quite
complex:

Zoomtext 7.11 only reads menu items (on state changes to "armed"),
when previously a menu has been opened (sending a state change
to either "focused" or "selected"). Due to a bug in Zoomtext 7.11,
it can't handle more than one level of menus, so it stopps reading
menu items as soon as the first submenu is closed.

The reason why Zoomtext 7.11 currently does read menu items, even after
a submenu has been closed, is a workaround in SO that suppresses the
state change event when a menu closes. This workaround can be
disabled by setting the environment variable
SAL_ACCESSIBILITY_ENABLE_MENU_SELECTED.

In case of a context menu, currently neither a "selected" nor a
"focused" state change is sent, so reading context menus does only
work after one has opened the first submenu or a menu of the menubar.

For the 6.1 Beta2 Oliver Braun will provide a "focused" state change
event when the context menu opens.