When you select the option "Event Status" in the canvas "Option" menu,
the current object info reports some object attributes.
In case of histograms, the integral from bin 1 to the bin pointed
by the mouse is also reported.
I have modified my version (will be 2.00/09) to report the integral
from the low bin selected with the slider in the DrawPanel.
You can obtain the same result on the command line with
h->Integral(binmin,binmax);
Rene Brun