Open and run the attached .exe file first posted by Kevin Chandler at Find lost dialog/window utility (using Autohotkey) V1.01 update (posted again by Tony Tieuli in a Reply at Drawing Rotate View dialogue box doesn't appear: any ideas on getting it back?). It will bring it to the front.
Edit: An alternative is to use the method described in the Reply below from Dan Pihlaja (thank you for posting that Dan; I thought I remembered seeing something somewhere about a method using the keyboard, but couldn't find it).