Fix the zoom issue

Author: ZhijieZhang

src/components/ToggleElementOverlay/ToggleElementOverlay.js

@@ -23,13 +23,19 @@ class ToggleElementOverlay extends React.PureComponent {
   }
 
   componentDidMount() {
+    core.addEventListener('documentLoaded', this.onDocumentLoaded);
     core.addEventListener('zoomUpdated', this.onZoomUpdated);
   }
-
+  
   componentWillUnmount() {
+    core.removeEventListener('documentLoaded', this.onDocumentLoaded);
     core.removeEventListener('zoomUpdated', this.onZoomUpdated);
   }
 
+  onDocumentLoaded = () => {
+    this.setState({ value: Math.ceil(core.getZoom() * 100).toString() });
+  }
+
   onZoomUpdated = () => {
     this.setState({ value: Math.ceil(core.getZoom() * 100).toString() });
   }