This is a Pro Sites feature suggestion. I checked the forums and didn't find anything related to this.
When accessing the Account page from the WP dashboard, it opens the page in the current window. This is a bit annoying since there's no simple, obvious to get back to the dashboard, particularly if the WP admin bar is disabled.
To make things a bit easier for new users I recommend either 1) open the page in a new window with target="_blank" (the easy way) or 2) embed the account/subscription form fields in the dashboard so customers don't even have to leave (ideal).
The regular signup page could remain as-is since it serves a purpose as a landing/conversion page, though I know it's being redone in an upcoming version of Pro Sites.
If anyone knows of a simple way to do this that I'm missing, let me know. Thanks.