Suggestions for enhancement
It would be very helpful for Ants to produce a list of all threads and their CPU usage over the selected sampling region. That would allow me to quickly identify which threads to concentrate on. I don't know where you would put this on the interface, but a thread summary would be pretty handy.
When I select a time range to study, there is nowhere on the screen that displays a) the total clock time in the selected region, and b) the total CPU time in the selected region. Both of these would be exceptionally useful in identifying whether it is the managed threads or the unmanaged threads that are contributing to the total CPU load. I suggest adding this information right at the bottom of the graph where it is always visible.