At least under Windows, if a box is resizeable, grabbing any edge and resizing a bit will make the whole window pop down into full view. Doesn't work with the (fixed-size) Print dialog, though. Changing monitor setups is the usual cause of these problems in the first place...
A temporary hookup to a second monitor might allow it to be grabbed and moved.
— | Word & InDesign to Kindle & EPUB: a Pro Guide (Amazon)