I am using Corona SDK 2014.2189
I found different results on these 2 implementations.
#1 - works as expected
local rect = display.newRect( 0, 0, 100, 100)
rect:setFillColor( 1, 0, 0 )
scrollView:insert( rect )
#2 - button does not respond to touch event and the position 0,0 is center of scrollView, not top left of screen
local rect = display.newRect( scrollView, 0, 0, 100, 100)
method#2 It will work well if i pass group from newGroup. It looks like the problem is in passing scroll view object to newRect function.
I am not sure if it has been fixed in daily builds or not. please let me know.