We also have the notion of "interactors" which allow you to add draggable widgets to a plot: http://ncnr.nist.gov/instruments/magik/calculators/calcR_wf....
To see the heatmap in action, you can look at: http://ncnr.nist.gov/ipeek/singleplotwindow.html?instrument=...
There are of course glitches, but hopefully you find some of this useful!