>
> Do you also disagree that those Emacs packages strive to emulate the 
> drop-down combo UI?
>

I don't know.  What I can tell is that when I wrote my vertical icomplete, 
I did not think a single second about drop-down combo UI's.  I just 
thought something like "I can't read these completion candidates presented 
horizontally, my eye has to move too much, I want them to be displayed 
right under the cursor."  (And yes, this "be displayed under the cursor" 
is not a standard feature of those packages.)

>> And, FWIW, I would very much dislike a "combo box like UI" to replace 
>> this.
>
> When you do need to use the Web browsers that implement that UI, do you 
> frequently regret they don't work like Ivy?
>

I don't understand your question.  I understood earlier that you find that 
browsers implement this in a prettier way, but now you seem to think that 
it works "better" in browsers.  But I don't know what is "better".

>>> Wholeheartedly agreed.  In particular with all that blank space at the 
>>> right side of the minibuffer window.
>>
>> I don't know what browser you use, but with both Chromium and Firefox 
>> you also have "all that blank space at the right side" of the drop-down 
>> list of candidates.
>
> No, those browsers never drop a list which is as wide as the 
> window/frame.  So they waste much less screen space.
>

I attach a screenshot of Chromium.  The frame is 2880 pixels wide, the 
"combo box" with completion candidates is 2472 pixels wide.  That's 86% of 
the frame width.  Okay, 86% is not 100%, but 86% is not "much less" than 
100%.