Incomplete return url after editing collection item

When browsing a collection in cms-app, the url contains many parameters (sorting options, page offset, etc). But after returning from editing an item, all those options but collection are lost. This is because _return hidden input in edit form is encoded using htmlentities_compat instead of urlencode, causing the lost of every parameters after the &.

Solution 1: add $cgi->return = urlencode ( htmlentities_reverse ($this->widgets['return']->getValue ($cgi))); to MailForm constructor (in the derived class).

Solution 2: create a Hidden MF_Widget encoding value using urlencode instead of htmlentities_compat.