If you're a clever-clogs scientist doing fancy things like producing run-plans that have a predictable bearing rate, or range between the participants then this is just up your street. If you request an XY Plot of two planning tracks, you can then configure the graph to update itself as the tracks change.
Here's how you do it:
Select your two tracks in the Outline View
Right-click on one of the tracks
Selectfrom the popup menu
From the popup dialog, select the calculation you're after
Then indicate which is the primary track (though it's irrelevant to many calcs)
Once the plot appears, check that the Auto-Sync toggle button in the graph toolbar is selected .
Now, when you drag or otherwise manipulate your tracks the graph will update to show the new relationship between the tracks. Clearly you un-set the auto-sync toggle to shop updating with the plot.