search position question

src/components/search/search-result.js

@@ -76,8 +76,9 @@ class SearchResult extends PureComponent {
     }
 
     handleScroll = throttle(() => {
-        let y = window.scrollY, headY = this.searchHead.current.offsetTop
-        if (y < this.prevScrollY) {
+        let y = window.scrollY, 
+            headY = this.searchHead.current.offsetTop;
+        if (y < this.prevScrollY && y > 0) {
 
             if (this.state.swipeDirection === this.swipeDown) {
 
@@ -114,7 +115,7 @@ class SearchResult extends PureComponent {
             })
 
         }
-        this.prevScrollY = y
+        this.prevScrollY = y;
     }, 0)
 
     render() {