Only redirect to a stored tab if it still exists

client/src/js/util/index.js

@@ -52,6 +52,10 @@ export function measureScrollBarWidth() {
 }
 
 export function find(arr, pred) {
+  if (!arr) {
+    return null;
+  }
+
   for (let i = 0; i < arr.length; i++) {
     if (pred(arr[i])) {
       return arr[i];