Ok another approach:
Install the addon ZGOO. it's for developers but can help you as well here!
If the error appears again move the mouse over this context menu entries and let it there.
Press RETURN to get into the chat and enter the following command and execute it with the RETURN key again:
In an upcoming ZGOO variable inspector window you can see a list of the information about the current control BELOW your moue (the popup menu entry).
Have a look at the function GetName() and what the name is that is shown there.
Or click thought GetParent() funciton to open the parent control of the context menu entry and check GetName() in there.
The name will probably/hopefully show you the name of the addon that "owns the popup window".