We've updated to 1.6.0.3 final, so I'm closing this.

Figured out a workaround until prototypejs is updated.  Fixed for 4.2.1.

Changes have been made in CVS for this ticket:

http://cvs.horde.org/diff.php/imp/docs/CHANGES?r1=1.699.2.344&r2=1.699.2.345&ty=u
http://cvs.horde.org/diff.php/imp/js/autocomplete.js?r1=1.3.2.4&r2=1.3.2.5&ty=u
http://cvs.horde.org/diff.php/imp/js/src/autocomplete.js?r1=1.3.2.4&r2=1.3.2.5&ty=u

Changes have been made in CVS for this ticket:

http://cvs.horde.org/diff.php/imp/docs/CHANGES?r1=1.1178&r2=1.1179&ty=u
http://cvs.horde.org/diff.php/imp/js/autocomplete.js?r1=1.7&r2=1.8&ty=u
http://cvs.horde.org/diff.php/imp/js/src/autocomplete.js?r1=1.7&r2=1.8&ty=u

Thinking about this more - this is *really* broken behavior.  I think 
this is blocking on IMP 4.2.1.  Given the hack solution given in the 
previous comment, we are better off using the latest pre-1.6.0.3 
version of prototypejs (especially since it provides some other fixes 
that are useful elsewhere).

We worked around the problem by adding code in the fixIEOverlapping 
function in imp/js/controls.js to calculate the proper absolute 
position for the autocompletion div.  This file has been stripped and 
renamed to autocomplete.js (as well as other changes to other files 
for other fixes) which is why we didn't submit this for use.  Anyway, 
here's the code if it's useful:



fixIEOverlapping: function() {

     Position.clone(this.update, this.iefix, 
{setTop:(!this.update.style.height)});

     this.iefix.style.zIndex = 1;

     this.update.style.zIndex = 2;

     //*** BEGIN Change ***

     // Need to set the left position bceause IE shifts it to the left 
for each added address

     var e = document.getElementById('to');

     var n = e.offsetLeft;

     var p = e.offsetParent;

     while(p&&p.tagName!='BODY')

     {

         n+=p.offsetLeft;

         p=p.offsetParent;

     }

     this.update.style.left = n;

     //*** END Change ***

     Element.show(this.iefix);

   }



Not elegant but it does work.  Sounds like the problem will go away in 
the near future anyway.

Then this is probably better marked as stalled, since the next version 
of prototypejs will fix this.

I would say no, unless someone is coming up with a stripped-down patch 
the exactly fixes this issue.

This is fixed if using the latest dev version of prototypejs.  I 
glanced at the code, but there have been so many changes to the 
positioning functions that there is little/no chance we would be able 
to do a clean patch to 1.6.0.2.  Don't know if this bug is nasty 
enough to upgrade to the latest dev version (?)

Confirmed.

When composing a message using IE6 or IE7, the address look up 
suggestion pop-up starts to move left as you add recipients.   Pretty 
much by the time the field (To, Cc, Bcc) starts to fill up and start 
scrolling existing entries to the left, the pop up will move to the 
left as well, eventually moving beyond the boundaries of the 
composition window.