The genomic scaffold filling problem has attracted a lot of attention recently. The problem is on filling an incomplete sequence (scaffold) [Formula: see text] into [Formula: see text], with respect to a complete reference genome [Formula: see text], such that the number of common/shared adjacencies between [Formula: see text] and [Formula: see text] is maximized. The problem is NP-complete, and admits a constant-factor approximation. However, the sequence input [Formula: see text] is not quite practical and does not fit most of the real datasets (where a scaffold is more often given as a list of contigs). In this paper, we revisit the genomic scaffold filling problem by considering this important case when a scaffold [Formula: see text] is given, the missing genes can only be inserted in between the contigs, and the objective is to maximize the number of common adjacencies between [Formula: see text] and the filled genome [Formula: see text]. For this problem, we present a simple NP-completeness proof, we then present a factor-2 approximation algorithm.