sc_require("theme"); // it is derived from dark, but will be available both under Ace and not. SC.AceTheme.Popover = SC.AceTheme.Dark.subtheme("popover"); SC.AceTheme.addTheme(SC.AceTheme.Popover); // there is a solid variety SC.AceTheme.SolidPopover = SC.AceTheme.Popover.subtheme('solid'); // and a shortcut to the solid variety. SC.AceTheme.addTheme(SC.AceTheme.SolidPopover.create({ name: 'solid-popover' }));