Computer Configuration > Administrative Templates > Firefox > Content Analysis (DLP)
Both
HKLM\Software\Policies\Mozilla\Firefox\ContentAnalysis
If this policy is enabled, Firefox will automatically allow DLP requests whose data comes from the same tab and frame - for example, if data is copied to the clipboard and then pasted on the same page. If this policy is disabled or not configured, Firefox will not pass DLP requests whose data comes from the same tab and frame to the DLP agent as normal.