Can't use individual form elements in node_edit page

A while ago with an earlier version of ctools (7.x-1.x branch) I was able to add individual form elements to various panel regions in the node_edit page. An update to the latest version has seen these options disappear from the "Add pane" modal form. What's the go here? Is this a deprecated feature, or is there another way to do this that I'm missing?

The elements I've already added into the panel are rendered as expected - it's just that I can't add any new ones.

See attached screenshots for examples:

You can see the individual fields that I added to the right hand side before the ctools update:

Now when I go to the "Form" group on the "add region" page, I can't see any options for fields.

If this has been deprecated; I urge this to be reconsidered as currently there is no flexible way to retheme node forms in Drupal 7, and is something that Panels would be amazing for (as opposed to nodeformcols for D6, which is OK but very inflexible).