web safe area 955 x 600?

[digitalecartoons]

For a maximized browser window on a 1024 x 768 monitor, Dreamweaver (and other sites) says that the web safe area is 955 x 600. I was wondering how this is calculated? I've tried it on a photoshop template: a screendump of a 1024x768 browser window with a scrollbar on the right. When I place a 955 x 600 graphic against the right scrollbar, the top menu and the bottom status bar, I still have about 1 cm of space to the left. I know dreamweaver takes into account the possible scrollbar, but what is dreamweaver thinking I might have on the left of my browser window?