Retrieving all work items in "In Progress" State
Accepted answer
As far as I can tell, only the ones within one project area. See https://rsjazz.wordpress.com/2012/11/19/using-expressions-for-automation/ and https://rsjazz.wordpress.com/2012/10/29/using-work-item-queris-for-automation/
Also note, that you might not even have access to all work items, if you don't have access to all project areas.