Everytime I try to use ctrl-shift-up or ctrl-shift-down inside of the new windows terminal preview, it scrolls the terminal view up or down. I tried going into the profiles.json file and set the "command" : "scrollDown" and "command" : "scrollUp" to "unbound" but it has no effect.
If I try to bind scollUp to something else, let's say ctrl+alt+b, then it correctly adds the keybind to the command. It seems like there's a default windows keybinding that is set to scroll the terminal view up and down using ctrl+shift+arrows.
Not sure if you found the answer, but I was looking for this too. Found the below in a microsfot devblog that works currently:
If there is a default key binding included in the defaults.json file that you would like to free up, you can set that key binding to null in your profiles.json.
{ "command": null, "keys": ["ctrl+shift+w"] }
Link to full article: https://devblogs.microsoft.com/commandline/windows-terminal-preview-1910-release/