Liberty Media Corporation v. The Bank of New York Mellon Trust Company, N.A. , C.A. 5702-VCL (April 29, 2011) affirmed, Del Supr Septemer 21, 2011.
Both Section 271 of the DGCL and many indentures provide that a corporation may not sell all or substantially all of its assets without stockholder approval. For years, a recurring problem has been how to apply that law to a series of asset sales that when taken all together amount to a sale of almost all the company's assets. This decision explains the so-called "step-transaction doctrine" under which such multiple sales may be aggregated to be considered one sale requiring stockholder approval.
The short [and probably too simplistic answer] is that when the sales each have their own business justification, the Court will not aggregate them.