Hello,
You could modify the theme to remove the ability or the icon. That would require cloning the theme in WHM > Themes > cPanel Themes area and then making revisions. I'm just pointing this out as it is possible to do with some work. The main files that handle this in x3 theme are /usr/local/cpanel/base/webmail/x3/index.html and /usr/local/cpanel/base/webmail/x3/js2/mail/pops.js ones.
To just remove the icon itself, you can edit /usr/local/cpanel/base/webmail/newtheme/index.html for these lines:
Code:
<cpanelfeature popaccts>
<td >
<div valign="top" align="center">
<a href="mail/passwdpop.html?redirectdomain=&email=<cpanel sprint="$authuser,@,0">&domain=<cpanel print="$CPDATA{'DNS'}">"><img src="<cpanel Branding="image(password)">" border="0" /></a><br><a href="mail/passwdpop.html?redirectdomain=&email=<cpanel sprint="$authuser,@,0">&domain=<cpanel print="$CPDATA{'DNS'}">"><cpanel langprint="ChangePassWebmail"></a>
</div>
</td>
</cpanelfeature>
Here the path newtheme is using the new theme you've cloned to revise. The default x3 theme should not be directly modified. After saving that file with the removed lines, the icon will no longer appear there. If they have a direct link to the page, they can still make modifications, so you'd want to then also revise the /usr/local/cpanel/base/webmail/newtheme/js2/mail/pops.js file to remove the functions to change the password there. Quite a few functions are in that file and it would need too many changes to post them here.
Hopefully, the above will be enough to help those until this feature request has been considered and possibly implemented in the future.
Thanks!