In latest version of DW the plugin manager does not check anymore the $conf['pluginmanager'] parameter to decide wether it should display itself in the admin page & handle plugins.
In a farm context it is a big problem as we cannot forbid the animals administrator to manage animals like before.
Some "if($this->disabled) return;" should be added in handle/render methods as well as where the menutext is computed (couldn't find that).
Rather than fixing this specific plugin it would probably be sensible to move disabling plugins to a configuration file within conf/. A simple list of disabled plugins should do. This would also lower the number of fileexists checks.
Should we provide a simple fix (in the plugin) for the next release?
yes, a simple fix by reenabling the old behaviour makes sense