can-set-size-constraint? in text%
Called before the editor's maximum or minimum height or width
is changed. If the return value is #f, then the
change will be aborted.
(This callback method is provided because setting an editor's maximum width may cause lines to be re-flowed with soft carriage returns.)
See also
on-set-size-constraint,
after-set-size-constraint, and
on-edit-sequence.