How to use Catalina window snapping feature? I keep reading about a window snapping feature in Catalina but I cannot for the life of me get it to work.
From https://www.hellotech.com/blog/the-best-features-macos-catalina:

All you have to do is drag an app to one side of the screen. When you see a transparent box fill that side of the screen, release the mouse, and the window will resize itself. If you push the app against the right or left side of your screen, the window will fill up that half of the screen.
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You can also drag an app to any corner to make the window fill a quarter of the screen. Or you can drag an app against the top of your screen to fill the screen with that window. Finally, you can drag a window to the bottom of your screen to make the window fill the center of your screen.

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From https://www.maketecheasier.com/snap-split-screen-windows-macos/:

Entering snap mode is very straightforward. All you have to do is click and drag any open window to one of the four sides or four corners of your display. Once a translucent box appears, release the mouse button. The window will now automatically snap into position.

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No matter what I do, I cannot get this to happen. No translucent box, no snapping.
Is there some setting I have to have enabled?
There's no &quot;translucent box&quot; in Catalina, that was for previous versions of macOS.  To do that, you would click and hold the green button.
Catalina uses the &quot;hover&quot; method.  Hover over the green button and you'll get a popup allowing you to select &quot;Full Screen,&quot; &quot;Tile Left,&quot; and &quot;Tile Right.&quot;
Personally, I've found macOS' window snapping feature a bit light on functionality.  I recently started using BetterSnapTool that allowed me to create custom snap areas anywhere on my desktops (multiple monitors).  I can even assign shortcuts so that I can snap my open windows to the preset monitor and size.  It costs $3, but (IMO) it is well worth it.
I've tested various other window managers that didn't work for me, but you might get better mileage out of them

Magnet ($3).  Intuitive and very useful. I couldn't use it because it conflicted with Think or Swim trading platform.

Spectacle (Free).  Worked well in El Capitan, however it's no longer maintained and was crashing in Catalina, though it may have also had a compatibility issue with Think or Swim.

Moom ($10).  Moom is short for Move and Zoom.  It works on a grid system and has the ability to remember layouts

Divvy ($14).  Another grid based window manager .  It allows you to &quot;divvy up&quot; your screen into snappable areas.

Rectangle (Free). Allows you to resize windows with keyboard shortcuts.  There's about 20 predefined shortcuts, and no way to create custom snap points/sizes.

Hookshot ($8).  Based on Rectangle and from the same developer. Uses modifier keys and mouse gestures to snap windows.