Update 10.13.6!

After updating High Sierra to 10.13.6 some programs snap to an narrow band at the top of screen and can not be resized vertically, also if moved vertically they snap back to the top of the screen. Of the programs I have looked at "Mail" and "Firefox" are unusable; "Safari", "iTunes", and "Photos" are presently working. How do I turn off the snap feature and vertically resize the windows of the programs that have gone haywire?

I am using an iMac (Retina 5K, 27-inch, Late 2015)