Since just clicking on the image in preview mode does nothing, it would be awesome if one could zoom-in while pressing the mouse button (without control).
It would be so much easier and faster to check focus. (1 click to zoom in while clicking vs ctrl+click to zoom in, ctrl+click to zoom out, total 4 clicks/buttons and 2 hands needed).
Text above pasted from comment on my question on Camerabits' Facebook page.