Visual C++ :: Pan Gesture In Desktop Application

I'm struggling with the pan gesture in a desktop application for my Surface Pro 2.

I simply want to pan (or "swipe" if you prefer) with two fingers, but it doesn't behave like I want it to. If I put two fingers on the screen and move them straight diagonally, I receive a series of client coordinates that are aligned in a vertical or horizontal direction. Only if I perform some circular motion, then it's suddenly possible to move diagonally and receive coordinates accordingly.

I've tried with MFC, by overriding CView::OnGesturePan. I've also tried with a sample project provided by Intel, that handles the GID_PAN message in WndProc to move a rectangle around, but with the very same result. The project can be downloaded from [URL] ... fordesktop.zip, so you can quickly reproduce the behaviour if you have a touch screen.

Code:
void GestureHandler::handlePan(HWND hWnd, GESTUREINFO gi) {
if (gi.dwFlags & GF_BEGIN) {
m_first.x = gi.ptsLocation.x;
m_first.y = gi.ptsLocation.y;

[Code] .....

I first thought it had to do with the points being too close to each other. I mean, if two points lies only one pixel apart, it can only result in eight different directions. But if I modify the code to only update "m_first" when the distance between the points are greater than some minimum distance, the points still keep being projected to a horizontal or vertical line relative to the first starting point.