In Sketchup 8, why is it that there is no back button? There have been times when I would accidently delete something and there's no way to undo that. The few times this happened to me really got me angry and had to start all over again, especially if I accidently delete a project that was grouped. In later versions of Sketchup, there is an Undo button that allows one to back up. Why do they find it necessary to have no back button, or a button that allows me to back up in Sketchup 8 if I make a mistake? If Sketchup 8 is supposed to have a back button, I can't find it no where.