Window flag: when set the window will accept for touch events outside of its bounds to be sent to other windows that also support split touch. When this flag is not set, the first pointer that goes down determines the window to which all subsequent touches go until all pointers go up. When this flag is set, each pointer (not necessarily the first) that goes down determines the window to which all subsequent touches of that pointer will go until that pointer goes up thereby enabling touches with multiple pointers to be split across multiple windows.