diff --git a/src/api/rest-api.js b/src/api/rest-api.js
index bc886bb..40329c2 100644
--- a/src/api/rest-api.js
+++ b/src/api/rest-api.js
@@ -21,8 +21,8 @@ class RestAPI {
   get(url) {
     return new Promise(function (resolve, reject) {
       request.get(makeURL(url)).end(function (error, res) {
-        if (res.status !== 200) {
-          reject();
+        if (res == null || res.status !== 200) {
+          reject(error);
         } else {
           resolve(JSON.parse(res.text));
         }
@@ -33,8 +33,8 @@ class RestAPI {
   post(url, body) {
     return new Promise(function (resolve, reject) {
       request.post(makeURL(url)).send(body).end(function (error, res) {
-        if (res.status !== 200) {
-          reject();
+        if (res == null || res.status !== 200) {
+          reject(error);
         } else {
           resolve(JSON.parse(res.text));
         }
@@ -45,8 +45,8 @@ class RestAPI {
   delete(url) {
     return new Promise(function (resolve, reject) {
       request.delete(makeURL(url)).end(function (error, res) {
-        if (res.status !== 200) {
-          reject();
+        if (res == null || res.status !== 200) {
+          reject(error);
         } else {
           resolve(JSON.parse(res.text));
         }
@@ -57,8 +57,8 @@ class RestAPI {
   put(url, body) {
     return new Promise(function (resolve, reject) {
       request.put(makeURL(url)).send(body).end(function (error, res) {
-        if (res.status !== 200) {
-          reject();
+        if (res == null || res.status !== 200) {
+          reject(error);
         } else {
           resolve(JSON.parse(res.text));
         }
diff --git a/src/containers/home.js b/src/containers/home.js
index 81ead97..ae74541 100644
--- a/src/containers/home.js
+++ b/src/containers/home.js
@@ -13,8 +13,6 @@ import { Container } from 'flux/utils';
 // import AppDispatcher from '../app-dispatcher';
 import VillasStore from '../stores/villas-store';
 
-import '../styles/home.css';
-
 class Home extends Component {
   static getStores() {
     return [ VillasStore ];
diff --git a/src/containers/visualization.js b/src/containers/visualization.js
index f2c33f2..9fd585f 100644
--- a/src/containers/visualization.js
+++ b/src/containers/visualization.js
@@ -23,11 +23,23 @@ class Visualization extends Component {
     return [ VisualizationStore ];
   }
 
-  static calculateState() {
+  static calculateState(prevState) {
+    if (prevState) {
+      return {
+        visualizations: VisualizationStore.getState(),
+
+        visualization: prevState.visualization,
+        editing: prevState.editing,
+        grid: prevState.grid
+      };
+    }
+
     return {
       visualizations: VisualizationStore.getState(),
 
-      visualization: {}
+      visualization: {},
+      editing: false,
+      grid: false
     }
   }
 
@@ -97,8 +109,6 @@ class Visualization extends Component {
       endpoint: 'localhost:5000',
       identifier: 'RTDS'
     });
-
-    this.setState({ editing: false });
   }
 
   componentDidUpdate() {
@@ -147,7 +157,7 @@ class Visualization extends Component {
           <Dropzone onDrop={item => this.handleDrop(item)} editing={this.state.editing}>
             {this.state.visualization.widgets != null &&
               this.state.visualization.widgets.map((widget, index) => (
-              <Widget key={index} data={widget} onWidgetChange={(w, i) => this.widgetChange(w, i)} editing={this.state.editing} index={index} />
+              <Widget key={index} data={widget} onWidgetChange={(w, i) => this.widgetChange(w, i)} editing={this.state.editing} index={index} grid={this.state.grid} />
             ))}
           </Dropzone>
 
diff --git a/src/stores/array-store.js b/src/stores/array-store.js
index 41123e8..8f2179d 100644
--- a/src/stores/array-store.js
+++ b/src/stores/array-store.js
@@ -43,11 +43,11 @@ class ArrayStore extends ReduceStore {
         return state;
 
       case this.type + '/added':
-        // state should always be immutable, thus make new copy
-        array = state.slice();
-        array.push(action.data);
+        // signal array change since its not automatically detected
+        state.push(action.data);
+        this.__emitChange();
 
-        return array;
+        return state;
 
       case this.type + '/add-error':
         // TODO: Add error message
@@ -59,7 +59,7 @@ class ArrayStore extends ReduceStore {
 
       case this.type + '/removed':
         return state.filter((item) => {
-          return (item !== action.data);
+          return (item !== action.original);
         });
 
       case this.type + '/remove-error':
diff --git a/src/stores/simulator-data-store.js b/src/stores/simulator-data-store.js
index 14b426b..38b69a3 100644
--- a/src/stores/simulator-data-store.js
+++ b/src/stores/simulator-data-store.js
@@ -12,6 +12,8 @@ import { ReduceStore } from 'flux/utils';
 import AppDispatcher from '../app-dispatcher';
 import SimulatorDataManager from '../data-managers/simulator-data-manager';
 
+const MAX_VALUES = 10000;
+
 class SimulationDataStore extends ReduceStore {
   constructor() {
     super(AppDispatcher);
@@ -43,6 +45,12 @@ class SimulationDataStore extends ReduceStore {
         // add data to simulator
         for (i = 0; i < state[action.identifier].signals; i++) {
           state[action.identifier].values[i].push({ x: action.data.timestamp, y: action.data.values[i] });
+
+          // erase old values
+          if (state[action.identifier].values[i].length > MAX_VALUES) {
+            const pos = state[action.identifier].values[i].length - MAX_VALUES;
+            state[action.identifier].values[i].splice(0, pos);
+          }
         }
 
         // update metadata
diff --git a/src/styles/home.css b/src/styles/home.css
deleted file mode 100644
index 5a74ef5..0000000
--- a/src/styles/home.css
+++ /dev/null
@@ -1,8 +0,0 @@
-/**
- * File: home.css
- * Author: Markus Grigull <mgrigull@eonerc.rwth-aachen.de>
- * Date: 02.03.2017
- * Copyright: 2017, Institute for Automation of Complex Power Systems, EONERC
- *   This file is part of VILLASweb. All Rights Reserved. Proprietary and confidential.
- *   Unauthorized copying of this file, via any medium is strictly prohibited.
- **********************************************************************************/