Non-plugin content elements not accessible when list_type not empty
Szenario: Admin creates a content element (CType='plugin'), chooses a valid plugin (e.g. 'powermail_pi1'), saves it and then decides it should be a CType='textmedia' instead. The so modified content element is then not accessible (editable) for editors that lack the right to edit said plugin. Even though it's a textmedia element now.
Somewhere in the access control management procedure the field 'list_type' seems to be taken into account even though it's irrelevant for non plugins.
A workaround would be to run this on the DB:
UPDATE tt_content SET list_type='' WHERE ctype != 'list' AND list_type != '';