webapp/course: only show the main scrollbar if necessary (otherwise there are two)
webapp/course: only show the main scrollbar if necessary (otherwise there are two)

DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,DrXyzzy/smc