hello af,

i believe that access to FF has not been a priority for the programmers because the windows operating system (as well as other o.s.'s) have the security features that govern who accesses the programs on the computer.

so setting up applications to have their own passwords would be redundant when windows itself can be set up with password protections.

in other words, windows is like a house. so either users can set up the front door to lock are be unlocked. but once that door is opened, everything inside the house becomes accessible.

additionally, windows can be set up for multiple user accounts. an administrative account provides all access to the machine. but other user accounts can also be set up that limits access.

also in windows 10, there is parental control features. i dont know how to use them. however, it may be possible for a parent to control or limit the use of any application by the child, per se.

last week, a user was having issues launching FF as it would immediately shut down when starting. we found there was a parental control app installed that would immediately turn off the FF browser.

Thank you for your answer. I just solve my problem by third party software.

you're welcome af .  :-)