ouch!;-) i did not quite think there would be use-cases.. more just wondering out aloud. if someone else has examples of their use-cases, i would be interested to read though those. the possibilities seem rather open-ended for now. my example was a somewhat isolated case - take groups plugin, do/do`not rename it; put it to another purpose than just 'groups'; trim a few ends, add a few ltttle features and.. a whole new world! (elgg) works for me..! my way out when i could figure which of the foss P.M. pkgs (there's too many out there) i liked enough to use without am extended learning curve or customizing. so this makes abt the 3rd or 4th time i've used 'groups' (almost unchanged) to create a new 'plugin' feature.

For my purpose this is one of the most essential features of Elgg. 
*thanks to the creator* 

Hi,

I upgraded Elgg to version 1.8.12. Now i have a problem with groups/edit. When i update a group profile all settings like title, description etcetera are emptied. When i disable AU subgroups the problem is gone.

My test instance has been 1.8.12 since it was released and it's working fine there.  Are you sure you're using the most recent version of AU subgroups?

I found the solution:

/mod/au_subgroups/views/default/groups/edit.php

<?php

/**
* Edit/create a group wrapper
*
* @uses $vars['entity'] ElggGroup object
*/

$entity = elgg_extract('entity', $vars, null);

$form_vars = array(
'enctype' => 'multipart/form-data',
'class' => 'elgg-form-alt',
);

echo elgg_view_form('groups/edit', $form_vars, groups_prepare_form_vars($entity));

i cannot delete a subgroup.... any help ? 

Are you using the most recent version of this plugin?  You're commenting on an older version here...