Fix line off error in checkbox
Fix line off error in checkbox

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