Try opening IE from the desktop and grabbing the scroll bar with the old school laptop method of holding down the physical left 'mouse' button in the type cover hovering on the scroll bar, then use another finger to move the scroll bar around. I tested this at a shop and there was so much delay between input and output that even the guy demoing it noticed.
Just tried this on all our Surfaces (Surface 1, Surface Pro 1, Surface 2, Surface Pro 2) with both a type cover 1 and a type cover 2 and I'm experiencing no delay with any combination of device and type cover at all. (I'm assuming you meant use one finger to click the left mouse portion of the trackpad and another finger to drag elsewhere on the trackpad - rather than on the screen to scroll?)
I agree with wkempf - the trackpad on the covers are pretty lousy - for example, I can never get 'click and drag' working on them, I think it either doesn't support it, or is too sensitive for my fingers. Worse thing is for the type cover 2 they've made it worse - they've gone from a smooth trackpad on the v1 that has a physical click, to a fabric trackpad on the 2 that doesn't have physical click feedback. Not a real world problem really, just use the touchscreen for what you need and for things like Visual Studio, I plug a wireless mouse into my pro anyway.