Sequoia offered shortcuts to auto resize windows, such as double-click on the upper edge of the title bar to get that window to extend all the way to the top of the screen size. That’s great, until you notice that you also double-click the title bar to dock a window and at times you double-click title bar ends up being interpreted as double-click top window edge. So, is there any immediate undo to that resize?
Window > Move & Resize > Return to Previous Size
sounds like the right thing, but at least here, it’s not doing anything.
The only time I’ve seen Window > Move & Resize > Return to Previous Size even selectable is when you use one of the other options in the Window > Move & Resize menu. It seems like Return to Previous Size should always work, whether it’s just drag resizing or one of the double-click actions, but it doesn’t seem to, unfortunately.
A simple click on the green button toggles full-screen mode, but an option-click (mostly) behaves as the old Zoom button did. It normally toggles between what the app considers its “ideal” size (sometimes that fills the screen) and whatever size you had before zooming.
But it’s app-dependent. For instance, Finder windows always shift to a computed size (the smallest size that can hold the icons in view), but doesn’t seem to un-zoom. Clicking it again just makes small changes to the window size.
With GNU Emacs, the first click goes to full-height, second goes to screen-filling, and the third click goes to the size of your last manual-resize.
With FileMaker, it follows the old Apple guidelines, toggling between the size you set and something based on content - the size of your layout, limited to the screen’s height and width.