The summary graph screen is a listing of any final destinations or intermediate hops from any of your destinations.  This summary gives you a way to compare multiple targets, and also gives you an easy one-glance summary of all the important parts of your network.

Adding targets to the summary screen

By default, when you trace to a new target, that final destination will automatically be added to the summary graph screen, and a time-graph for that summary will be added as well.

In addition, if you want to manually add a target (or any intermediate router) to the summary graph, just right-click on that hop in the trace graph and select "Show on Summary Screen".

At any time, you can turn on or off a time graph by double-clicking on that router / target in the upper graph.

From the summary screen, you can switch to the trace graph by right-clicking on a host and selecting the menu option "Show trace graph".

You can sort the list of targets by clicking on a graph heading.  Clicking again reverses the sort order.

Resizing the time graphs

Once you get a few targets on the summary screen (and a few time graphs), you may wish you could resize (make them taller or shorter) the time graphs but are unable to because of the existence of the scrollbar on the time graph area.

To resize all of the time graphs, scroll to the last summary graph (the scroll bar should be at the bottom of its range).  Now, float your mouse cursor between the lowest graph and the one above it - you should get a resize pointer and you can then size the graphs at your pleasure.  All time graph will resize to match. 

Time periods on the summary screen (ie: "samples to include")

The summary graph screen works slightly different than some of the other graphs in that the upper summary graph may have any number of targets, all using different collection methods and possibly different trace intervals.  Because you might have different trace intervals (and even different time scales), the "Samples to Include" concept is replaced by a "Graph focus time".  This Graph focus time is a time-based setting, rather than a sample count based setting like the trace graph uses.

As a related note, you can also enter a time period on a trace graph - and PingPlotter will convert that to a sample count - in that case, though, it's a one-time deal.  On the summary screen, the time period is constant and the sample count (internally) is dynamically updated as samples are collected.