I've reposted the following here, originally titled 'Dangerous FMP v16 Advanced Behaviour' in 'Report a Product Issue', as suggested by TSPigeon:
FileMaker Pro v16 Advanced 18.104.22.168/Windows 10 and Mac OS X Sierra 10.12.6
Although this is technically not a bug, we feel this too dangerous not to be addressed. Control D and Command D keyboard shortcuts are used throughout FileMaker and become a natural thing to do when duplicating many elements such as records, script steps, etc.
If using the Data Viewer 'Watch' tab and wanting to duplicate an entry, rather than clicking the double plus duplication button, the temptation is to use the aforementioned keyboard shortcut. The behaviour is that the focus is automatically taken away from the Data Viewer back to the record and the current record is duplicated.
As many of us are using multiple displays to run palettes, script debugger, data viewer, etc. this is even more dangerous as it is very easy to miss that a record has been generated.
If this commonly used shortcut is not to be included within the data viewer, focus should still remain within it and no record interaction should take place, particularly as recent releases has enabled less use of a mouse and more capability for the keyboard.