In CS2, when I zoom an image down using the zoom tool, the canvas resizes down in proportion, fitting the image.  In CS5, however, I go from image size of  perhaps 66% and zoom down to 33% or so, the image goes down but is within a canvas of the original 66% size, meaning I need to grab a corner and bring in the canvas to match the image.  If the image is zoomed up, I have to then expand the canvas to reveal the entire image again.  The canvas will not grow or shrink with the image.

Surely there is some simple preference I have missed to allow the canvas to sync in size with the image when zooming the image down or up? I feel a bit dumb asking this but surely CS5 did not eliminate that capability as found in earlier versions of Photoshop.™®.    Thanks for any input.   TomDart