So Firefox popped up showing that an update was available. I decided "sure" let it update. Upon browser launching after update now its FULL SCREEN BROWSER with no controls and no directions on how to get back to the way the browser was before. So I had to mess around and figure it out.
I took screenshots showing what they dump you off at after the update to 38.0.1
And you need to move your pointer to the very top of the screen to then have the hidden toolbar to show, and then right-click in this area to get the menu with 2 options to appear in which they have HIDE TOOLBARS checked. You need to uncheck that, and then your not done there. Now you get your URL bar, but the taskbar is still missing as well as the menu controls of Firefox are still missing. You need to go back to the menu by right clicking to top toolbar again and selecting to "Exit Full Screen Mode". This then brings back the interface menu selections from the prior version of firefox that you had configured prior.
Nothing like an update saying "HERE !!!!!!!!!!!!... You WILL be forced checkout our latest features and oh by the way you need to figure out how to get out of this on your own!"
Pic 1 is what they dump you off at.
Pic 2 is a useless menu drop down that doesnt help anyone wanting to get back to prior browser setting.
Pic 3 is finding the hidden at top toolbar and unchecking the "hidden" to no longer be hidden.
Pic 4 ( Shown in 2nd post since the sum of the images exceed 700KB per post ) is going back to this toolbar and deselecting the "Exit Full Screen Mode" which shows no check box to even show that its enabled as seen in Pic 3 but it is enabled by default once 38.0.1 is installed.
Then everything goes back to the way it was as far as layout to 37.x.x that you ran prior to the update.
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