def getElementUnderMouse(widget, x,y):
        element = widget.getElement()
        hit = isIn(element, x, y)
        if hit:
            child_elem = getTargetInChildren(element, x, y)
            if child_elem:
                return child_elem
            return element
        return None
Return the most specific element in widget that contains (x,y).
dataset/ETHPy150Open anandology/pyjamas/library/gwt/dnd/utils.py/getElementUnderMouse