SQL management studio hangs when opening after being closed down on dual screen
I have found the answer on the server fault site:
Unfortunately I can't vote the guy up (https://serverfault.com/users/166318/eirik-toft) as I don't have any reputation on that site (or this site that my question got migrated too) However, I thought I would leave this answer here as a signpost to his answer.
To work around the issue I 'alt-tab' to select the main sql window. Then 'alt-space' to get the context menu then 'm' to select move, then I used the arrow keys to brings the hidden dialogue box into view.
It might be a bit late for this but I suffered from the same problem. Happens to me when I close it on the second monitor with it attached at the corner. The simple solution to me was to just hitting escape with the focus being on the Manager. That closes the dialog so you can control the manager again. Then move it to the main monitor and try to connect. A lot simpler then trying to move the dialog into focus.