The ProgressMonitor dialog can be closed in following ways :
1. 'Cancel' button is pressed
2. Dialog Close button is pressed
3. Escape key is pressed

If the ProgressMonitor dialog is closed, ProgressMonitor.isCanceled() method used to return 'true' in only cases (1) and (2) above.
This fix corrects the behavior where ProgressMonitor.isCanceled() method will return 'true' in case the ProgressMonitor dialog is closed by pressing Escape key.

There is low compatibility impact of this fix :
This change may impact user code that (incorrectly) assumes ProgressMonitor.isCanceled() will return false even if the ProgressMonitor dialog is closed as a result of pressing Escape key.
Also, with this change, now there is no way to get the ProgressMonitor dialog out of way whilst having progress continue.