ShellDeleteRegistrar typedef
ShellDeleteRegistrar =
VoidCallback Function(bool delete())
Registers the shell's delete with its host (host embedding API spec
C-3, as Slice 4's S-16 ruled): delete deletes the selection as the
select tool's idle Delete does and answers whether it did. Returns the
withdrawal, which the shell calls on dispose, as
ShellSettleRegistrar's.
Implementation
typedef ShellDeleteRegistrar = VoidCallback Function(bool Function() delete);