I've downloaded and installed the Content Management Filter, but I think that the interface is a bit ugly still with all the drop downs, and it doesn't actually achieve what I had hoped.
Basically, I'm looking for a way to put a row of tabs at the top of admin/content/node so that a managing user can easily select to display just one type of node (or all nodes).
Is there a module for this?
If not, what's the best strategy? How do I tie in with the filtering already in place on this page?
View Bulk Operations (VBO) is a module that, through Views, allows you to create a page similar to the page visible in /admin/content/node. As the module allows to replace the content of that page with the content of a view, you can filter the list of the nodes following all the criteria that Views allows you to set.
The features of the module are not just those; the module allows you to select all the nodes listed in the view, and apply to them the action that is selected under "Update." The module is very useful for administrators, and it allows also to change the page that lists all the user registered in a Drupal site with a view with similar functionalities.
I would just use Views to override it to get the fields I need as exposed filters that are required.
