When you drag the Straighten tool, it shrinks and rotates the cropping border to the angle you’d need to straighten the photo (without leaving any white gaps in the corners). Now all you have to do is double-click anywhere inside that cropping border to lock in your straightening. Figure 4 shows the photo after I straightened it using the Straighten tool. The exact angle of your correction (circled in Figure 4) is displayed in the toolbar. If you don’t like the result of your first attempt at straightening, click the Clear button on the far right side of the toolbar to clear the straightening line and return the Straighten tool to the toolbar. Then try again.