Q:

How do I remove dead links from the whisker search bar in xubuntu 16.04? 

I have searched through the entire menu editor, deleting everything I do not want.  However if I use the search feature in whisker the entries remain as dead links. 

A:

I found it by removing the links from
cd ~/.local/share/applications
rm gog_com-Dragonsphere_1.desktop
rm unity-editor*

For some reason, I was given a prompt to remove these, but for some reason they persisted under multiple deletes.  They were removed simply with sudo privileges. 