Theme development (widgets and menus)

I’m trying to work on a new theme and using User Level Theme to switch between them. However, it’s presenting problems with the widgets and menus. It seems that they are specific to the theme in one respect however changing settings in one theme affects the display in the other theme.

If figured out the menus, but I can’t seem to test the new theme without wiping out my widgets in the sidebar of the live theme.