Three fingers drag doesn't work when fingers are vertically

Question

I have a problem with three fingers drag gesture in OS X Lion on my Macbook Air 2011. This gesture can be turned on in trackpad preferences. I have no problems when my fingers are horizontally like in video instruction:

But often I use laptop from the bed, and my fingers are vertically:

In this position system often (but not always) doesn't recognize the gesture and act like two fingers gesture.

Is it common behavior, or bug in my laptop? Can it be fixed?

Answer 1

Try using only the top half of your trackpad when doing this.

The lowest finger might get interpreted as the "button finger" whose movements are ignored.