DLP does not flag email attachments in Outlook 2016 with Drag and Drop

Hello, 

I have been enabling various DLP's at our company in test groups, I have them working well in terms of what data is getting flagged.  However in Outlook 2016 if a user selects attach a file the prompt comes up but if they drag and drop the same file in a new email the prompt does not come up.   I know this has to do with Outlooks Temp Secure folder which the location can be found in the registry at these locations-

Outlook 97: HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Outlook\Security
Outlook 98: HKEY_CURRENT_USER\Software\Microsoft\Office\8.5\Outlook\Security
Outlook 2000: HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Outlook\Security
Outlook 2002/XP: HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security
Outlook 2003: HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Security
Outlook 2007: HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Security
Outlook 2010: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security
Outlook 2013: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Security
Outlook 2016: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Security

But I cannot get the folder location to change by altering the registry key, Microsoft just changes it back.  Is there some type of workaround for this?  I have looked for various 
settings that may help such as the GPO Outlook ADMX and so on but I cannot seem to find where to make the change to get this to work.  Any help would be appreciated greatly.

Thanks,