I've installed CCSM and followed the steps mentioned in several other posts on this issue an nothing has worked. When I drag a window to the top left it just drags it off the screen instead of making it resize to take up half my monitor. I rely pretty heavier on this feature.
I figured it out. I had to enable windows tiling in dconf editor.
select gnome > mutter:check "windows tiling"
select shell > overrides:check "windows tiling"
close dconf editor
worked for me.