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ui/src/index.js

@@ -57,6 +57,7 @@ browserHistory.listen(() => {
 
 window.addEventListener('keyup', event => {
   const escapeKeyCode = 27
+  // fallback for browsers that don't support event.key
   if (event.key === 'Escape' || event.keyCode === escapeKeyCode) {
     dispatch(disablePresentationMode())
   }