To move quickly between Grid and Loupe view, use the shortcuts “G” for Grid and “E” for Loupe (I think of “enlarge” so that I can remember the shortcut). When in Loupe view, double clicking on the image will take you back to grid view (and vice versa).
Comments
I running Lion OS on a MACBook Pro with the released academic version of LR4. I am unable to get a double-click on an image in Grid view to take me to the same image in Loupe view (or vice versa). I can find no settings addressing this. Help, please.
Sorry, but I have not heard of this issue. I would post the issue to either of these forums to see if other customers are experiencing the same problem and if so, if they have found a solution.
http://forums.adobe.com/community/lightroom
http://feedback.photoshop.com/photoshop_family