Answer:
Simply Double Click on the Title bar of the Dialog box to reduce it to it default size,
Step-by-step explanation:
Some times you might want to save a workbook in a spreadsheet programme and you are faced with this kind of problem, all you need do is to Double Click on the Title Bar of the Dialog (Save As Dialog, Open Dialog) box to quickly reduce it to it default size before moving it to one side of the screen as shown in the picture below.
Note: when you double click it either maximize or restore the dialog box.