Thank you for pointing out this problem! I forgot about the icon displayed in the context menu.

I looked into the documentation and the icon is being picked up from a default icon value that is specified in a manifest file (packaged along with the extension).

However, I am unable to find any programming API that allows me to change the context menu icon (the documentation indicates that only icons for the sub-menus of the main context menu entry can have customizable icons). I will continue to look into this, in case I've missed something.