Eon,

here is a list of the existing work_spaces in the admin-section
1- admin_html_head
2 - admin_main_menu
3 - admin_main_menu_contents
4 - new_image_form
5 - image_uploaded
6 - image_edit
7 - default_thumb_created
8 - options

so the names of these workspaces show obviously where they will be activated, for example everything you define in an Admin-AddOn, which you assign to the workspace "default_thumb_created" will be executed after the thumbnail is created

I hope this helps you a little bit

I am sure there will be some more workspaces in future and maybe some names might change in BETA-status, but it is a great idea to add functionality to the admin-part of PP