WordPress version: 3.5.1
WordPress SEO version: 1.4.7
Theme: Montezuma 1.1.9
I did this:
Went into the post edit screen. The upload images buttons did not work - opened in a new page. The "Edit" permalink button did not work. The HTML editor buttons did not work. On "HTML" view, there were no buttons at all. Add Custom Field button did not work.
Upon deactivating all plugins, functionality came back.
Turning plugins one by one back on saw the issue resurface after I reactivated WordPress SEO by Yoast.
I think this is either a theme / plugin conflict as I've never seen this issue before and we use this plugin exclusively - really I'm just posting this to help troubleshoot if issue crops up again...