How to stop security prices from appearing in price editor automatically?

[William Sunday]

I just upgraded from GnuCash 2.4 to 2.6 and I see that calculated stock 
prices from transactions are appearing automatically in the Price Editor.

This is definitely a change from 2.4 and an unwelcome one. I want to 
control the prices entries in the Price Editor. Furthermore, the 
_incorrect_ price is entered if I mistype the stock share amount or 
price paid and not fixed even I correct the mistake in the transaction.

How can I stop GnuCash from being so helpful and entering these prices 
in the Price Editor?