Neatline plugins should just be available to an exhibit if they've been activated in the Omeka plugins panel

[jeremyboggs]

For all our Neatline widgets/plugins, we have a 3-step process to actually use them:

1. Upload the Neatline widget/plugin to the Omeka plugins directory and activate it in the Omeka Admin panel, like you do Neatline and any other Omeka plugin.
2. Declare that you wish to use that widget/plugin on an individual Neatline exhibit by typing out the widget/plugin name in the Widgets field on the Exhibit Settings form.
3. Select that plugin again under the Styles tab in the Neatline editor.

It seems that step 2 or step 3 could be removed, and step 2 seems the most likely candidate to me.