I've customized the default layout as I like:
When I press CMD+LEFT/RIGHT, windows move to my defined tiles. Great!
But if I drag a window towards the left or right side of the screen, it doesn't work - it just tiles the screen down the middle, same as before.
I can hold CTRL to enable my layout, but why is the original layout the default? The original "down the middle" layout doesn't even exist anymore, I replaced it, as you saw.
What gives?
At settings > multitasking
disable the active screen edges.
At Zorin appearance > Windows > Advanced Window Tiling
click on the cogwheel and scroll down to screen edges and enable it and at "Choose how windows snap to screen edges" select the middle option
"Adaptive" or the right option "Granular".
Make sure that the correct layout in the indicator is selected which you want to use.
Thank you so much! Adaptive was the right setting for me.
The default is kind of confusing, I think? I mean, since we have the customizable layouts, why would the default be to use something else? Sort of odd.
I come from Windows and the layout manager in PowerToys, so maybe it's just a matter of expectations. 
Yes, I agree, that's actually a bit confusing, and I didn't realize before that you also have to disable the active screen edges in the settings app - otherwise, it doesn't work and overwrites the settings you make in the Zorin tiling shell extension.
This does seem a bit like a "bug"? Controls that don't apply to the mode you've selected probably shouldn't be displayed?
