no, min/max would be displayed as all other indicators.
to calculate, think to Chaikin/twiggs Money Flow, when MT open the chart it would calculate the value tick by tick to have the min/max for every candle, this (I believe) could be very heavy for MT/processors so MT could calculate the indicator only in real time, using a pointer to save min/max, and dislay on the chart the indicators from that moment.
the same if you change the set of the chart/indicator, MT begin to display the indicator only from that moment
thx