src/vs/workbench/contrib/extensions/browser/extensionsActions.ts/SetColorThemeAction/computeEnablement
class SetColorThemeAction:	private computeEnablement(colorThemes: IWorkbenchColorTheme[]): boolean {
		return !!this.extension && this.extension.state === ExtensionState.Installed && this.extensionEnablementService.isEnabledEnablementState(this.extension.enablementState) && colorThemes.some(th => isThemeFromExtension(th, this.extension));
	}