diff --git a/controllers/controller.number.js b/controllers/controller.number.js
index 4a63372..1af4683 100644
--- a/controllers/controller.number.js
+++ b/controllers/controller.number.js
@@ -85,6 +85,7 @@ GUI.NumberController = function() {
 	        numberField.focus();
 	        numberField.select();
         }
+		if(slider) slider.domElement.className = slider.domElement.className.replace(' active', '');
         draggedNumberField = false;
         clickedNumberField = false;
 		if (_this.finishChangeFunction != null) {
@@ -106,6 +107,8 @@ GUI.NumberController = function() {
 		GUI.makeUnselectable(_this.parent.domElement);
 		GUI.makeUnselectable(numberField);
 		
+		if(slider) slider.domElement.className += ' active';
+		
 		py = y;
 		y = e.pageY;
 		var dy = py - y;
diff --git a/controllers/slider.js b/controllers/slider.js
index b3ad28a..d129942 100644
--- a/controllers/slider.js
+++ b/controllers/slider.js
@@ -46,6 +46,7 @@ GUI.Slider = function(numberController, min, max, step, initValue) {
 		x = px = e.pageX;
 		_this.domElement.setAttribute('class', 'guidat-slider-bg active');
 		_this.fg.setAttribute('class', 'guidat-slider-fg active');
+		numberController.domElement.className += ' active';
 		onDrag(e);
 		document.addEventListener('mouseup', mouseup, false);
 	}, false);
@@ -54,6 +55,7 @@ GUI.Slider = function(numberController, min, max, step, initValue) {
 	var mouseup = function(e) { 
 		_this.domElement.setAttribute('class', 'guidat-slider-bg');
 		_this.fg.setAttribute('class', 'guidat-slider-fg');
+		numberController.domElement.className = numberController.domElement.className.replace(' active', '');
 		clicked = false;			
 		if (numberController.finishChangeFunction != null) {
 			numberController.finishChangeFunction.call(this, numberController.getValue());
diff --git a/gui.css b/gui.css
index db24012..5543fd5 100644
--- a/gui.css
+++ b/gui.css
@@ -86,7 +86,8 @@ a.guidat-toggle:hover {
 	float: right;
 }
 
-.guidat-controller input:hover { 
+.guidat-controller input:hover.
+.guidat-controller.number.active { 
 	background-color: #444;
 }