I used to have the blank permission screen, but after having performed the upgrade steps, all I get is my blog in an iFrame instead of the permissions page.
The URL is:
In my settings:
I've put the blog's URL for the support URL and both the normal and secure Canvas URL.
My Page Tabs section doesn't look like the screenshot in the doc.
When I select iFrame, I have to type the full URL.
I'm using this for both the normal and secure URL
I left the "Edit URL" empty