CRM 2016 / Ribbon Workbench / Hiding the Delete button on Email Activity

Using this potentially great tool  called Ribbon Workbench. I am trying to hide the Delete button on an Email Activity as so: 

I goto the appropriate area in the Ribbon workbench change the button to hide "Delete" But I get this error upon the solution Import:

Reasons:
1:The FetchXml (xml snippet>) is invalid.  Failure while calculating dependencies for SavedQuery

This error was asked in Ribbon workbench , but there is no answer

https://ribbonworkbench.uservoice.com/forums/155731-general/suggestions/6991462-error-2-0-0-7-failure-while-calculating-dependenci

I decided to export a Default Solution and locate the corresponding xml in the Customizations.xml file. Is it a simple matter of removing the bad XML and importing back ? Has anyone encountered this error before ? I'd prefer to just hide the "Delete" button in the XML since I'm in it. Which would be better way of handling this ?

I could not find the saved query in the application itself, just in the xml file. This was a migration from CRM 4.0. 

Any help would be appreciated.Thanks...