Ancient Greek apostrophe marking elision

[Mark E. Shoulson via Unicode]

On 1/27/19 11:08 AM, Michael Everson via Unicode wrote:
> It is a letter. In “can’t” the apostrophe isn’t a letter. It’s a mark of elision.  I can double-click on the three words in this paragraph which have the apostrophe in them, and they are all whole-word selected.

That doesn't work when I try it: I double-click on the "a" in "can’t" 
and get only the "can" selected.

This does not necessarily prove anything; my software (Thunderbird) is 
arguably doing it wrong.

~mark