GWT makes it easy to create a scrolling panel within an HTML driven web site, by using the ScrollPanel class. ScrollPanel itself expands into a div tag containing the overflow attribute; specifying which axes the scroll bars land on translate into overflow-x or overflow-y attributes in the generated HTML DOM object.
And the iPad (and iPhone and iPod Touch) do not allow you to scroll within the overflow tags; the touch-drag gesture only scrolls the entire page.
What this means is if you are putting together a GWT application that you want to work on the iPad, the natural instinct to create a root panel the full size of the screen and tossing in a ScrollPanel area in the lower right that resizes with the window is incorrect. Instead, you are better off generating your GWT code so that it generates the properly sized HTML, and scroll around the GWT application using the window’s scroll bars.