Whether an edge's target has an origin: S (what can open it, or the
generic handle) for a pushed screen; none for a tab switch (it restarts the
stack). A tab definition pushed by a screen-opening source — or by
a source type that may be one (TabEntryReading both) — is an
ordinary frame and keeps an origin.
Whether an edge's target has an origin:
S(what can open it, or the generic handle) for a pushed screen; none for a tab switch (it restarts the stack). A tab definition pushed by a screen-opening source — or by a source type that may be one (TabEntryReadingboth) — is an ordinary frame and keeps an origin.