I elected to update 34 applications. During the update process I received several error messages to the effect that the update could not be downloaded. So I later returned to the update utility and again elected to update all 34 applications. As soon as I clicked the OK or Start button, I decided I would like to update only a few at a time to determine which apps were generating the error messages. So I clicked the "Cancel" button, only to be reminded that there is no apparent way to cancel the entire Update operation without clicking "Cancel" 34 times, in this case.
For updates that include a large number of apps, it would be helpful to be able to click a single button to cancel the entire update procedure. (I am unaware of any way to do this currently.)