The admin site has a feature where it can show a pop-up window for some

actions, mostly selecting or creating related objects. We had some logic in the

admin_actions tag that was supposed to hide the sidebar in these windows, but

that logic was broken (since it was ORing two mutually-exclusive tests). I

fixed it to never even call admin_actions for pop-up windows, but that

exposed some issues with the CSS.
This change fixes all of that. The pop-up windows still show the header, which

I'm undecided on.

Opened a pop-up from the admin site and saw that it no longer showed the

sidebar.