System Tray Dropbox opens wrong application

This has to be file association "thing", but I'm not sure how to get to the solution. Ubuntu 16.04 TDE 14.0.7 I just added dropbox (for my existing Dropbox account) to a computer where it was not yet installed. Everything works "OK" ... .... except: Clicking on the System Tray object brings up the Dropbox menu. Then clicking on "Open Dropbox Folder" brings up Kid3 !!!! (kid3: the mp3 sound tag editor) I'm pretty sure 'it' wants to launch a file manager, but I do not know how to look behind the curtain of the System Tray object and see what it is attempting to do. And, if I go into Trinity Control Center >> TDE Components >> File Associations -- I see I might have a thousand or more file types and associations. But, I do not know how Dropbox is issuing the request -- e.g., I do not know what file type is involved. I must be overlooking something to debug this. What? Thank you, Jonesy -- Marvin L Jones | Marvin | W3DHJ | linux Pueblo, Colorado | @ | Jonesy | FreeBSD __ 38.238N 104.547W | jonz.net | DM78rf | OS/2 SK