diff --git a/htdocs/frontend/index.html b/htdocs/frontend/index.html
index 419e8c5..f60a404 100644
--- a/htdocs/frontend/index.html
+++ b/htdocs/frontend/index.html
@@ -20,12 +20,13 @@
 	<script type="text/javascript" src="javascripts/flot/jquery.flot.crosshair.js"></script>
 	<script type="text/javascript" src="javascripts/flot/jquery.flot.selection.js"></script>
 
+	<script type="text/javascript" src="javascripts/helper.js"></script>
 	<script type="text/javascript" src="javascripts/init.js"></script>
-	<script type="text/javascript" src="javascripts/entity.js"></script>
+	<script type="text/javascript" src="javascripts/options.js"></script>
+	<script type="text/javascript" src="javascripts/functions.js"></script>
 	<script type="text/javascript" src="javascripts/entities.js"></script>
 	<script type="text/javascript" src="javascripts/wui.js"></script>
-	<script type="text/javascript" src="javascripts/helper.js"></script>
-	<script type="text/javascript" src="javascripts/functions.js"></script>
+	<script type="text/javascript" src="javascripts/entity.js"></script>
 	
 	<link rel="stylesheet" type="text/css" href="stylesheets/ui-lightness/jquery-ui-1.8.10.css" />
 	<link rel="stylesheet" type="text/css" href="stylesheets/jquery.treeTable.css">
diff --git a/htdocs/frontend/javascripts/entity.js b/htdocs/frontend/javascripts/entity.js
index 8afd4ff..b8c342a 100644
--- a/htdocs/frontend/javascripts/entity.js
+++ b/htdocs/frontend/javascripts/entity.js
@@ -218,7 +218,7 @@ Entity.prototype.getDOMRow = function(parent) {
 						$('#entity-' + entity.uuid + ((parent) ? '.child-of-entity-' + parent.uuid : '') + ' input[type=checkbox]')
 						.attr('checked', state);
 						entity.active = state;
-					});
+					}, true); // recursive!
 					
 					vz.wui.drawPlot();
 				})
@@ -287,11 +287,9 @@ Entity.prototype.updateDOMRow = function() {
 		$('.last', row)
 			.text(vz.wui.formatNumber(this.data.tuples.last()[1], true) + this.definition.unit);
 		
-		if (this.definition.interpreter == 'Volkszaehler\\Interpreter\\MeterInterpreter') { // sensors have no consumption
-			$('.consumption', row)
-				.text(vz.wui.formatNumber(this.data.consumption, true) + this.definition.unit + 'h')
-				.attr('title', vz.wui.formatNumber(this.data.consumption * (year/delta), true) + this.definition.unit + 'h' + '/Jahr');
-		}
+		$('.consumption', row)
+			.text(vz.wui.formatNumber(this.data.consumption, true) + this.definition.unit + 'h')
+			.attr('title', vz.wui.formatNumber(this.data.consumption * (year/delta), true) + this.definition.unit + 'h' + '/Jahr');
 		
 		if (this.cost) {
 			$('.cost', row)
diff --git a/htdocs/frontend/javascripts/options.js b/htdocs/frontend/javascripts/options.js
index e20418c..5a12af7 100644
--- a/htdocs/frontend/javascripts/options.js
+++ b/htdocs/frontend/javascripts/options.js
@@ -66,7 +66,7 @@ vz.options.plot = {
 		hoverable: true,
 		autoHighlight: false
 	}
-}
+};
 
 vz.options.saveCookies = function() {
 	for (var key in vz.options) {
diff --git a/lib/Interpreter/SensorInterpreter.php b/lib/Interpreter/SensorInterpreter.php
index 52c94c2..675ea55 100644
--- a/lib/Interpreter/SensorInterpreter.php
+++ b/lib/Interpreter/SensorInterpreter.php
@@ -73,7 +73,8 @@ class SensorInterpreter extends Interpreter {
 	 */
 	public function getAverage() {
 		if ($consumption = $this->getConsumption()) {
-			return (3600 * 1000 * $consumption) / ($this->last[0] - $this->first[0]);
+			$delta = $this->last[0] - $this->first[0];
+			return (3600 * 1000 * $consumption) / $delta;
 		}
 		else { // prevents division by zero
 			return 0;
@@ -108,6 +109,9 @@ class SensorInterpreter extends Interpreter {
 			$last = $next;			
 			$next = $data->next();
 		}
+		
+		$this->first = reset($tuples);
+		$this->last = end($tuples);
 
 		return $tuples;
 	}