diff --git a/src/components/WindowViewer.js b/src/components/WindowViewer.js
index c6c8b03f58438636d41093aea223b116a4e7b3cd..367ce8753a198416f60df31c706f6eb37ce8e033 100644
--- a/src/components/WindowViewer.js
+++ b/src/components/WindowViewer.js
@@ -76,7 +76,7 @@ export class WindowViewer extends Component {
     }
 
     // only accept changes of at least 1 pixel, to limit the re-rendering
-    if (!height || Math.abs(height - size.height) > 1) {
+    if (typeof height === 'undefined' || Math.abs(height - size.height) > 1) {
       setWindowHeight(windowId, size.height);
     }
   }