Make a copy of monitor data

src/reducers/monitors.js

@@ -6,7 +6,7 @@ const reducer = function (state, action) {
     if (typeof state === 'undefined') state = initialState;
     switch (action.type) {
     case UPDATE_MONITORS:
-        return action.monitors;
+        return [...action.monitors];
     default:
         return state;
     }