Juri Linkov <juri@linkov.net> writes:
>>> A possible workaround would be to check the special property
>>> 'first-completion'.  But then when the logic uses text properties,
>>> why not to use more text properties that indicate that a candidate
>>> is deselected (and remove highlighting in this case) instead of
>>> moving point somewhere outside of the candidate?
>>
>> Even if we work around this with text properties, I think it's nice for
>> deselection to be usually determined by location of point.  I think
>> that's easier to understand for the user - they should be able to
>> deselect or reselect something purely by moving point around, it
>> shouldn't require text property manipulation.
>
> I agree that it's better to indicate deselection by moving point.
>
> After more testing I found a small problem:
>
>   M-x calc TAB TAB
>
> When the selected candidate is
>
>   calc-dispatch (C-x *)
>
> then point is moved before the suffix "(C-x *)",
> and after editing it is selected on RET.

Ah, good catch.  Fixed (by using 'completion--string to detect whether
point is on a completion rather 'mouse-face)