I haven't found this problem discussed in the forum so I will share my experience.
I have a (Invoice) layout in form view based on a table "Invoice". On this layout I have several fields from a different table "client" (Name, etc.)
When I invoke "create new record" both a new client and new invoice record are created.
I kept running into trouble while entering the new client information: the program would occasionally jump to an existing invoice record and if I didn't see this happen I would overwright the existing client information (not good!) BTW the new client record and new invoice record were created, the program just wasen't on them anymore.
In troubleshooting I found that if I tabbed through the client fields for the new record everything worked correctly, but if I moused into one of the client fields the layout would jump to the first record in the client table.
It turns out the problem was created by leaving the default "delineate fields on current record only" option checked in the layout setup. When this option is un-checked the problem goes away.
So now I only leave the "delineate fields..." option checked on layouts showing list view where this option works great.
The "delineate fields on current record only" seems to be dangerous in form view.
Just thought you would like to know.