Ctrader chart cannot be enlarged

I inserted six evelope like deviation 0.10, 0.15, 0.20, 0.25, 0.30, 0.40 to ctrader one minute chart however one minute chart is too small to see well. I cannot enlarge chart more than 25pips chart scale. I prefer chart to be scale 5pips. I keep click mouth on price on chart and move up and down then chart can be enlarged up to 25pips only and cannot enlarge like 5pips chart scale.