What Is Adding Multiple Entries To Dropdown Menu?

[NeuroticPixels]

It's not pChat.
It's not Junkee 2018.
It's not Inventory Insight.
It's not LootAlert.
It's not PersonalAssistant.
It's not ItemPreview. (Edit/Update: It was in fact ItemPreview, but not the only problem. So I got a false positive when tested.)
It's not LibMediaProvider.



I can't figure out which addon or library is causing multiple entries in my chat's dropdown menu.
When I had Master Merchant installed, it was even worse. MM had 3 entries for its price-to-chat feature and Inventory Insight had 3 entries as well.
Without Master Merchant, I'm down to just double entries from Inventory Insight.

Anyone know if there are specific addons known to cause this?
Or which libraries touch the dropdown menu?

Any tips on figuring out the culprit without disabling everything and re-enabling until it's found?