Summary:
When "New" is pressed, the button should become disabled, because
the file is empty and there is nothing to lose. The "New" button
should only be enabled when there is text to lose by pressing it.
Otherwise, there is no way in the code to disable the button except
at startup, which does not make much sense.
Reviewers: ajwillia.ms, zmike, bu5hm4n
Reviewed By: ajwillia.ms
Tags: #examples
Differential Revision: https://phab.enlightenment.org/D6512