I had my DebugView window open and noticed a strange message appear while my computer was basically idling:

ThumbPosition got called! That never happens.
Sweet. A developer somewhere has a sense of humor. So, where exactly did this debug message come from? Based on the proc ID in the debug window I found that it was Messenger:

Oh you silly MSFTies. This begs the question, what exactly is going on in Messenger that "never happens"?
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