Releasing the button advances the selection and wraps to zero. The
cycle-menu minimum-entry preference controls whether a popup can open.
Keyboard Press opens it when eligible; otherwise, or if opening fails,
Press advances as Down does. Without a popup, Up and Down wrap;
Top/PageUp and Bottom/PageDown select the first and last entry. With a
popup, these keys change its provisional highlight; Press accepts a
highlight other than -1, and Window Close cancels.
A mouse press to the right of the cycle image opens an eligible popup
when drawing is permitted. Pointer motion changes its highlight.
SELECTUP or a subsequent SELECTDOWN accepts a highlight other than -1;
other closing mouse codes cancel. The popup is a nonactivating,
borderless Intuition window on the object's screen. Preferences control
its position and recessed entries; a menu larger than the screen is
refused, not scrolled.
With a nonzero ObjectID, Export writes the current selection as one LONG
to the supplied Dataspace. Import finds that ID and sets Active from its
first LONG. Both return zero and ignore storage/set failures. Import
does not validate record size; provide a matching LONG record and a live
Dataspace. With ObjectID zero, neither performs data access.