Yosemite – funny you suggest, I did that right after I posted this. Right now I’m running Sideblog 3.4 from Kate Glasis, Sidebar Widgets 1.0.20060711 from Automattic all on WP 2.0.4. There is no actual Sideblog widget to pop in the sidebar from the Sidebar Widgets editor in Presentation but other widgets are there.
All is restored. In my Sidebar Widgets editor my sidebar category wasn’t checked. Duuuuuuhhhh!
Thanks for posting this thread. It helped me troubleshoot a problem I was having with Kate Glasis’s sideblog 3.4 after updating to wordpress 2.0.4.
After (re)activating the sideblog plugin, the widget was not available in admin/presentation/sidebar widgets. After reading here, I found the category I had assigned to the plugin (asides) was no longer checked (in admin/options/sideblog). Once the asides category was checked the plugin option appeared in the sidebar widgets.