I'm using linear regression drawing tool on ninjatrader 7 and 8.

I have noticed that if I draw linear regression channel diagnoally across two points say connecting the lowest and the highest points in a trend, I get exactly the same thing if I were to draw the regression channel horizontally, instead of diagonally. which means that regression channel is drawn across the X axis, without any input from the Y axis, which of course is the price.

so how are we drawing regression channels on ninjatrader without the component of price being taken into account. am I doing something wrong here?

You are wrong in your assumption that the regression channel does not take into account the price. However, the price is taken from the price bars and not from the position of your mouse pointer.

With your mouse pointer you only select the first and the last bar of the regression channel. The regression channel is then calculated from all prices inside that interval.