A possible reason can be that you are in permanent Private Browsing mode (Always use Private Browsing mode; Never Remember History). In permanent Private Browsing mode all windows you open are PB mode windows and you do not get the purple mask. You only see the purple mask if you open a New Private Window in a regular session.

• https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history
• https://support.mozilla.org/en-US/kb/common-myths-about-private-browsing

I got and 2 Firefox update yesterday, when I restarted, I could not open Firefox, I had to reinstall Firefox. now in private viewing icon will not display, which is all I use when on line, then, even with my email and pass word saved in settings, I had to get a code to to get into this account.... What is going on...????

  Why do I need a 362638 code to sign in....???

  Why can I not get an in private icon when getting on line...???

  Why did I have to reinstall Firefox, even when a window came up in 5 other attempts, 

asking if I wanted to make changes to my account...????

  Do I need to install another Browser...????

You do not see the purple mask when you are in permanent Private Browsing mode (Always use Private Browsing mode; Never Remember History), so if this mask is hidden then it is likely you are already in PB mode.

• https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history
• https://support.mozilla.org/en-US/kb/common-myths-about-private-browsing