diff --git a/source/WindowScroller/WindowScroller.js b/source/WindowScroller/WindowScroller.js
index e9d7e6b1a..314fad885 100644
--- a/source/WindowScroller/WindowScroller.js
+++ b/source/WindowScroller/WindowScroller.js
@@ -37,8 +37,7 @@ type Props = {
   onScroll: ({scrollLeft: number, scrollTop: number}) => void,
 
   /** Element to attach scroll event listeners. Defaults to window. */
-  scrollElement: ?Element,
-
+  scrollElement: ?(typeof window | Element),
   /**
    * Wait this amount of time after the last scroll event before resetting child `pointer-events`.
    */