When you use the keyboard shortcut to zoom in (command +) or zoom out (command -) in Photoshop the window scales along with the image. If you haven’t gotten used to this quirky default behavior yet there is a one-click fix to get it out of your life forever.
Well, at least until the next time you have to drop your preference file. Go to Photoshop > Preferences > General (command K) and click off “Zoom Resizes Windows”. Now the keyboard commands behave the same as the zoom tool. If your missing the good times you used to share with this behavior, take solace in knowing that you can bring it back just by moving your thumb over. You can use the alternate zoom behavior by adding option to the key command. Simply press (option command +) for zoom in and (option command -) for zoom out to bring back the glory days of window scale and zoom.