Delta time marker and peak search measurements

I use to graph appearcances and disappearances of many events. In such case, it would be very usefull and quicker to have delta time informations given by makers (even coupled markers from one graph to an other).
What do you think about this ??

do you want to mark a region in the graph and see how long the time span is?

Yes, I want to mark a region in a graph, then mark an other region in a graph and see how long the time span is between these 2 events.

think there is a feature request for that, not sure