When you pan the horizontal or vertical direction first, it will lock the scroll direction so you can only scroll in horizontal or vertical direction. This is called "Railed" scrolling. You can freely touch and move your finger on the screen, so the Railed Scrolling is helpful to make a better scroll result.

You can disable the Railed Scrolling by setting the C1Zoom.IsHorizontalRailEnabled property and C1Zoom.IsVerticalRailEnabled property to False, like the following code: