IBM Mainframe Forum

I guess if a dataset is APF protected and when you try to edit it, BROWSE will be substituted automatically.

on a professional forum guessing is just a waste of time for everybody.
( even worse when the guess is completely wrong )

instead of guessing better spend time meditating on

Introduction to the New Mainframe: z/OS Basics
http://www.redbooks.ibm.com/abstracts/sg246366.html

and on the whole series of
ABCs of z/OS System Programming
available here
http://www.redbooks.ibm.com

to save You from guessing here is the link to the first volume of the series
http://www.redbooks.ibm.com/abstracts/sg246981.html

APF protected

Besides guessing wrong, there is actually no such thing as "APF protected". Perhaps you are thinking of "APF authorized" or "RACF protected". In either case, you are wrong about why it switches to browse.