Changes have been made in Git (master):

commit d866a3129f1933f7a74dd1551349288fd4c8b0f9
Author: Michael J Rubinsky <mrubinsk@horde.org>
Date:   Thu Jul 10 13:57:45 2014 -0400

     Bug: 13336 Fix removing device state when multiple accounts exist 
on the same device.

     Conflicts:
             horde/admin/activesync.php

  horde/admin/activesync.php                       |    9 +++++++--
  horde/templates/activesync/device_table.html.php |   10 +++++-----
  2 files changed, 12 insertions(+), 7 deletions(-)

http://github.com/horde/horde/commit/d866a3129f1933f7a74dd1551349288fd4c8b0f9

Thank you!

Fixed for 5.2.1

Changes have been made in Git (FRAMEWORK_5_2):

commit 01b26397a1668fa25e2849f6b3b4710678544bf8
Author: Michael J Rubinsky <mrubinsk@horde.org>
Date:   Thu Jul 10 13:57:45 2014 -0400

     Bug: 13336 Fix removing device state when multiple accounts exist 
on the same device.

  horde/admin/activesync.php                       |   10 ++++++++--
  horde/templates/activesync/device_table.html.php |   10 +++++-----
  2 files changed, 13 insertions(+), 7 deletions(-)

http://github.com/horde/horde/commit/01b26397a1668fa25e2849f6b3b4710678544bf8

Nevermind. In my testing, it just so happened that the entry I was 
removing was the one that existed in that array.

If you actually look at the value of the this.devices hash, you will 
see there is a different entry for each device/user combination.

I see this:
$('uid').setValue(this.devices[id.substr(7)].user);

and that seems wrong as a device has several users

It's defined in javascript when the button click is caught.

Look in activesyncadmin.js

I've just tested again and it deletes the entry below it. The device 
has 7 accounts.
We're using Horde_ActiveSync_State_Sql

I've noticed that the button has a remove_deviceID variable, but I 
couldn't find where the uid is defined.

Actually, no. We already differentiate that when the form is 
submitted. I just tested with two accounts on the same device, and 
clicking remove on one entry removes the correct account's state.

You are going to have to find out why this does not work this way 
locally for you.

What state driver are you using for activesync? You can start to look 
in Horde_ActiveSync_State_Sql::removeState() or 
Horde_ActiveSync_State_Mongo::removeState() depending on the driver in 
use.

Ah. That makes more sense. I probably didn't differentiate accounts vs 
device_id on those buttons.

Yes, that's the page I'm talking about as well.

Maybe I should have mentioned that the URL of the page is:
horde/admin/activesync.php

One device can have several email accounts which are synchronised with 
Horde, that's the reason I didn't know how to name an entry from that 
list.

See if you can reproduce it when removing one of the many entries (not 
the last one) linked with one device.

I'm not sure if the state makes a difference. I was trying to remove 
entries for accounts which wouldn't sync and we're shown as 
unprovisioned.

What do you mean by "removed the wrong email address".  Email 
addresses have nothing to do with that page. Do you mean it removed 
the wrong device?  If so, I cannot reproduce. I am *constantly* 
removing devices from that page during testing and do not have any 
issues.

On the activesync page listing all the email accounts which are 
connected to the system, we're presented with 3 buttons: Wipe, remove 
and Block.

Clicking on "remove", removed the wrong email address from the list