there was a bug in share.js so the checbox was always unchecked
var user = '<li data-uid_shared_with="'+uid_shared_with+'">';
user += '<a href="" class="unshare" style="display:none;"><img class="svg" alt="Unshare" src="'+OC.imagePath('core','actions/delete')+'"/></a>';
user += uid_shared_with;
- user += '<input type="checkbox" name="permissions" id="'+uid_shared_with+'" class="permissions" "+checked+" />';
+ user += '<input type="checkbox" name="permissions" id="'+uid_shared_with+'" class="permissions" '+checked+' />';
user += '<label for="'+uid_shared_with+'" '+style+'>can edit</label>';
user += '</li>';
}