Well the case is here and here is excerpt.... take a look and this site may have some interesting conversation for you.
Laws, Life, and Legal Matters - Court Cases and Legal Information at Leagle.com - All Federal and State Appeals Court Cases in One Search: "Indeed, because the sole basis upon which Wells Fargo asserted its right to possession of the property was its 'duly perfected' legal title obtained in the nonjudicial foreclosure sale, the validity of Wells Fargo's title had to be resolved in the unlawful detainer action. 'Under section 1161a, Code of Civil Procedure, a purchaser who has acquired the title at such trustee's sale must prove that the property was sold in accordance with section 2924 of the Civil Code under a power of sale and that title under the sale has been duly perfected. Under such unlawful detainer statutes title to the extent required by section 1161a not only may but must be tried. . . . [Citations.] The bleak language of the judgment which merely restored possession to [the grantee] is a sufficient adjudication of her ownership in view of the issues tendered.' (Bliss v. Security-First Nat. Bank (1947) 81 Cal.App.2d 50, 58-59, italics added [stipulated judgment arising from unlawful detainer action brought under section 1161a held to bar subsequent claims for quiet title and to set aside trustee's sale].)"