The scroll position of the output window reset to the bottom of the window whenever something new is outputted.
This brings up an issue when you have a rogue script printing messages endlessly, and are trying to scroll up in the output to see previous messages.
for i = 1,1000 do print("Output" .. i) end game:GetService("RunService").RenderStepped:connect(function() print("Can't scroll!") end)
And a video: