I am developing an add-in for PowerPoint 2007 & 2010 using VSTO 4. My add-in needs to take different actions when PowerPoint starts depending on how PowerPoint was started. If the user has started PowerPoint with the default/blank template (e.g. from a PowerPoint icon in the Windows Start menu) I need to do one thing but if the user opens PowerPoint with a different template e.g. by opening a POTX file from Windows Explorer I need to do something else.
Is there a reliable way to detect how the user opened PowerPoint? Any hints/clues welcome.