This experimental investigation replicates previous investigations of the effects of left margin screen background color hue to signal lesson sections on declarative knowledge and extends those investigations by adding a measure of structural knowledge. Participants (N = 80) were randomly assigned to receive 1 of 4 computer-based lesson treatments that consisted of color or no color lessons crossed with color or no color structural knowledge and declarative knowledge posttests. A disordinal interaction was observed, lesson color had a significant positive effect on the structural knowledge posttest (effect size d = 0.41) but had a non-significant effect on the declarative knowledge posttest (d = -0.17). A memory context effect was not observed. Designers of screen-based instructional materials should consider the commonsense notion that screen background color hues that signal lesson sections will tend to more strongly overlay the lesson organization onto the learner's memory organization. (Contains 2 tables and 1 figure.)