diff --git a/htdocs/frontend/index.html b/htdocs/frontend/index.html
index 64559dd..e9bb849 100644
--- a/htdocs/frontend/index.html
+++ b/htdocs/frontend/index.html
@@ -38,9 +38,16 @@
 <div id="content">
 	<div id="headline">
 		<h2 id="title"></h2>
-		<div id="links">
-			<button id="snapshot"><img src="images/image.png" alt="snaptshot" /> Snapshot</button>
-			<button id="permalink"><img src="images/link.png" alt="permalink" /> Permalink</button>
+
+		<div id="export">
+			<img alt="export" src="images/export.png" />
+			<select>
+				<option value="default" style="background-image: url(images/export.png)" selected="selected">Export...</option>
+				<option value="permalink" style="background-image: url(images/link.png)" >Permalink</option>
+				<option value="png" style="background-image: url(images/image.png)" disabled="disabled" >Snapshot</option>
+				<option value="csv" style="background-image: url(images/table.png)" >CSV</option>
+				<option value="xml" style="background-image: url(images/xml.png)" >XML</option>
+			</select>
 		</div>
 		<br style="clear: both" />
 	</div>
@@ -151,7 +158,7 @@
 			<form method="get" target="_blank">
 				<table>
 					<tr class="property"><th>Eigenschaft</th><th>Wert</th></tr>
-					<tr class="property"><td>Middleware:></td><td><input type="text" id="entity-create-middleware" /></td></tr>
+					<tr class="property"><td>Middleware:</td><td><input type="text" id="entity-create-middleware" /></td></tr>
 					<tr class="property"><td>Typ:</td><td><select id="enti"name="type" size="1"></select></td></tr>
 					<tr class="property"><td>&Ouml;ffentlich:</td><td><input type="radio" name="public" value="1"> ja&nbsp;&nbsp;<input type="radio" name="public" value="0"> nein</td></tr>
 					<tr class="property"><td>Titel:</td><td><input type="text" name="title" value="K&uuml;hlschrank" /></td></tr>
diff --git a/htdocs/frontend/javascripts/entities.js b/htdocs/frontend/javascripts/entities.js
index 0287d92..2c47eab 100644
--- a/htdocs/frontend/javascripts/entities.js
+++ b/htdocs/frontend/javascripts/entities.js
@@ -81,7 +81,7 @@ vz.entities.each = function(cb, recursive) {
 	for (var i = 0; i < this.length; i++) {
 		cb(this[i]);
 		
-		if (recursive) {
+		if (recursive && this[i] !== undefined) {
 			this[i].each(cb, true);
 		}
 	}
@@ -151,7 +151,7 @@ vz.entities.showTable = function() {
 							} finally {
 								$.when(queue).done(function() {
 									// wait for middleware
-									$.when(from.loadDetails(), to.loadDetails).done(vz.entities.showDetails);
+									$.when(from.loadDetails(), to.loadDetails).done(vz.entities.showTable);
 								});
 								$(this).dialog('close');
 							}
diff --git a/htdocs/frontend/javascripts/entity.js b/htdocs/frontend/javascripts/entity.js
index 0f40663..843541c 100644
--- a/htdocs/frontend/javascripts/entity.js
+++ b/htdocs/frontend/javascripts/entity.js
@@ -83,7 +83,7 @@ Entity.prototype.loadData = function() {
 		success: function(json) {
 			this.data = json.data;
 		
-			if (this.data.tuples.length > 0) {
+			if (this.data.tuples && this.data.tuples.length > 0) {
 				if (this.data.min[1] < vz.options.plot.yaxis.min) { // allow negative values for temperature sensors
 					vz.options.plot.yaxis.min = null;
 				}
@@ -112,16 +112,22 @@ Entity.prototype.showDetails = function() {
 				$(this).dialog('close');
 			},
 			'Löschen' : function() {
-				vz.load({ // TODO encapsulate in own method
-					controller: 'entity',
-					context: this,
-					identifier: entity.uuid,
-					url: entity.middleware,
-					type: 'DELETE',
-					success: function() {
-						$(this).dialog('close');
-					}
+				entity.cookie = false;
+				vz.entities.saveCookie();
+				
+				entity.delete().done(function() {
+					vz.entities.each(function(it, parent) {
+						if (entity == it) {
+							var array = (parent) ? parent.children : vz.entities;
+							array.remove(it);
+						}
+					}, true);
+		
+					vz.entities.showTable();
+					vz.wui.drawPlot();
 				});
+				
+				$(this).dialog('close');
 			}
 		}
 	});
@@ -330,6 +336,19 @@ Entity.prototype.updateDOMRow = function() {
 	}
 };
 
+/**
+ * Permanently deletes this entity and its data from the middleware
+ */
+Entity.prototype.delete = function() {
+	return vz.load({
+		controller: 'entity',
+		context: this,
+		identifier: this.uuid,
+		url: this.middleware,
+		type: 'DELETE'
+	});
+}
+
 /**
  * Add entity as child
  */
@@ -345,7 +364,7 @@ Entity.prototype.addChild = function(child) {
 		data: {
 			uuid: child.uuid
 		},
-		type: 'post'
+		type: 'POST'
 	});
 }
 
@@ -353,13 +372,17 @@ Entity.prototype.addChild = function(child) {
  * Remove entity from children
  */
 Entity.prototype.removeChild = function(child) {
+	if (this.definition.model != 'Volkszaehler\\Model\\Aggregator') {
+		throw new Exception('EntityException', 'Entity is not an Aggregator');
+	}
+
 	return vz.load({
 		controller: 'group',
 		identifier: this.uuid,
 		url: this.middleware,
 		data: {
 			uuid: child.uuid,
-			operation: 'delete'
+			type: 'DELETE'
 		}
 	});
 };
@@ -374,7 +397,7 @@ Entity.prototype.each = function(cb, recursive) {
 		for (var i = 0; i < this.children.length; i++) {
 			cb(this.children[i], this);
 			
-			if (recursive) {
+			if (recursive && this.children[i] !== undefined) {
 				this.children[i].each(cb, true); // call recursive
 			}
 		}
diff --git a/htdocs/frontend/javascripts/init.js b/htdocs/frontend/javascripts/init.js
index 8d16f18..23d7c32 100644
--- a/htdocs/frontend/javascripts/init.js
+++ b/htdocs/frontend/javascripts/init.js
@@ -84,7 +84,7 @@ $(document).ready(function() {
 	// chaining ajax request with jquery deferred object
 	vz.capabilities.load().done(function() {
 		if (vz.capabilities.formats.contains('png')) {
-			$('#snapshot').show();
+			$('#export option[value=png]').removeAttr('disabled');
 		}
 		
 		var queue = new Array;
diff --git a/htdocs/frontend/javascripts/wui.js b/htdocs/frontend/javascripts/wui.js
index adffbfd..35abb8a 100644
--- a/htdocs/frontend/javascripts/wui.js
+++ b/htdocs/frontend/javascripts/wui.js
@@ -41,8 +41,21 @@ vz.wui.init = function() {
 	$('button, input[type=button],[type=image],[type=submit]').button();
 	$('button[name=options-save]').click(vz.options.saveCookies);
 	$('button[name=entity-add]').click(this.dialogs.init);
-	$('#permalink').click(function() { window.location = vz.wui.getPermalink(); });
-	$('#snapshot').click(function() { window.location = vz.wui.getSnaplink(); }).hide();
+	
+	$('#export select').change(function(event) {
+		switch ($(this).val()) {
+			case 'permalink':
+				window.location = vz.wui.getPermalink();
+				break;
+			case 'png':
+			case 'csv':
+			case 'xml':
+				window.location = vz.wui.getLink($(this).val());
+				break;
+				
+		}
+		$('#export option[value=default]').attr('selected', true);
+	});
 	
 	// bind plot actions
 	$('#controls button').click(this.handleControls);
@@ -83,25 +96,31 @@ vz.wui.dialogs.init = function() {
 		width: 530,
 		resizable: false
 	});
-	$('#entity-add.dialog > div').tabs();
-	
-	// load public entities
-	vz.load({
-		controller: 'entity',
-		success: function(json) {
-			var entities = new Array;
-			json.entities.each(function(index, json) {
-				entities.push(new Entity(json));
-			});
+	$('#entity-add.dialog > div').tabs({
+		show: function(event, ui) { // lazy loading public entities
+			if (ui.index != 1) {
+				return; // abort, we are not in public tab
+			}
+		
+			vz.load({
+				controller: 'entity',
+				success: function(json) {
+					var public = new Array;
+					json.entities.each(function(index, json) {
+						public.push(new Entity(json));
+					});
 
-			entities.sort(Entity.compare);
-			entities.each(function(index, entity) {
-				$('#entity-public-entity').append(
-					$('<option>').html(entity.title).val(entity.uuid).data('entity', entity)
-				);
-			});
+					public.sort(Entity.compare);
+					vz.middleware[0].public = public;
 			
-			vz.middleware[0].public = entities; /* store */
+					$('#entity-public-entity').empty();
+					public.each(function(index, entity) {
+						$('#entity-public-entity').append(
+							$('<option>').html(entity.title).val(entity.uuid).data('entity', entity)
+						);
+					});
+				}
+			});
 		}
 	});
 	
@@ -168,7 +187,7 @@ vz.wui.dialogs.init = function() {
 	});
 	
 	$('#entity-create form').submit(function() {
-		$(this).attr('action', $('#entity-create-middlware').val() + '/channel.json');
+		$(this).attr('action', $('#entity-create-middleware').val() + '/channel.json');
 		$('#entity-add').dialog('close');
 	});
 	
@@ -206,15 +225,17 @@ vz.wui.getPermalink = function() {
  *
  * @return string url
  */
-vz.wui.getSnaplink = function() {
-	var uuids = new Array;
+vz.wui.getLink = function(format) {
+	var entities = new Array;
 	vz.entities.each(function(entity, parent) {
 		if (entity.active) {
-			uuids.push(entity.uuid);
+			entities.push(entity);
 		}
 	}, true); // recursive!
 	
-	return vz.options.middlewareUrl + '/data/' + uuids[0] + '.png?' + $.param({
+	var entity = entities[0]; // TODO handle other entities
+	
+	return entity.middleware + '/data/' + entity.uuid + '.' + format + '?' + $.param({
 		from: Math.floor(vz.options.plot.xaxis.min),
 		to: Math.ceil(vz.options.plot.xaxis.max)
 	});