When multiple Processes (including Proxy Processes) are run on a single object, they appear in the "Routing/Process History" table as shown below.
Each Process has a checkbox in the first column. However, the information only displays for one checkbox at a time, and only if that checkbox is selected when no other boxes are checked. To clarify - if I wanted to switch process displays in the image below, I would first have to uncheck the top box and then check another row's entry. If I select another row and then deselect the top box, the data display will not properly refresh.
This is a bit clumsy and unintuitive. If only one selection can be displayed at a time, radio buttons should be used, not checkboxes. Ideally, multiple selections could be made and the information would display task history from the union of the two processes.