diff --git a/management/univention-management-console-module-ucr/umc/js/ucr.js b/management/univention-management-console-module-ucr/umc/js/ucr.js
index 59fa709..6ec7967 100644
--- a/management/univention-management-console-module-ucr/umc/js/ucr.js
+++ b/management/univention-management-console-module-ucr/umc/js/ucr.js
@@ -106,24 +106,7 @@ define([
 				label: _( 'Save' ),
 				style: 'float: right',
 				callback: lang.hitch(this, function() {
-					var keyWidget = this._form.getWidget('key');
-					tools.umcpCommand('ucr/validate', {'key': keyWidget.get('value')}).then(lang.hitch(this, function(data) {
-						var keyIsValid = data.result;
-						if (keyIsValid) {
-							// save the UCR variable
-							keyWidget.setValid(true);
-							this._form.save();
-							this.hide();
-						} else {
-							// show invalid UCR variable message
-							var invalidMessage =  _('A valid key must contain at least one character and can only contain letters, numerals, and "/", ".", ":", "_" and "-".');
-							if (keyWidget.get('value').indexOf(': ') !== -1) {
-								invalidMessage = lang.replace('{0}<br>{1}', [_('The sequence ": " in the name of a UCR variable is not allowed.'), invalidMessage]);
-							}
-							keyWidget.setValid(false, invalidMessage);
-							keyWidget.focus();
-						}
-					}));
+					this._form.save();
 				})
 			}, {
 				//FIXME: Should be much simpler. The key name should be enough
@@ -165,7 +148,10 @@ define([
 				this._position();
 				this.standby(false);
 			}));
-			this._form.on('saved', lang.hitch(this, function() {
+			this._form.on('saved', lang.hitch(this, function(success) {
+				if (success) {
+					this.hide();
+				}
 				this._position();
 				this.standby(false);
 			}));
@@ -173,6 +159,8 @@ define([
 
 		clearForm: function() {
 			var emptyValues = {};
+			this._form.getWidget('key').setValid(true);
+			this._form.getWidget('value').setValid(true);
 			tools.forIn(this._form.get('value'), function(ikey) {
 				emptyValues[ikey] = '';
 			});
diff --git a/management/univention-management-console-module-ucr/umc/python/ucr/__init__.py b/management/univention-management-console-module-ucr/umc/python/ucr/__init__.py
index 589063f..5ae5ebd 100644
--- a/management/univention-management-console-module-ucr/umc/python/ucr/__init__.py
+++ b/management/univention-management-console-module-ucr/umc/python/ucr/__init__.py
@@ -31,6 +31,8 @@
 # /usr/share/common-licenses/AGPL-3; if not, see
 # <http://www.gnu.org/licenses/>.
 
+from io import BytesIO
+
 from univention.lib.i18n import Translation
 from univention.management.console.base import Base, UMC_Error
 from univention.management.console.config import ucr
@@ -46,6 +48,18 @@
 _ = Translation('univention-management-console-module-ucr').translate
 
 
+class UCRKeySanitizer(StringSanitizer):
+
+	def _sanitize(self, value, name, further_arguments):
+		value = super(UCRKeySanitizer, self)._sanitize(value, name, further_arguments)
+		b = BytesIO()
+		if not validate_key(value, b):
+			error_message = b.getvalue()
+			self.raise_validation_error('%s %s' % (_('A valid UCR variable name must contain at least one character and can only contain letters, numerals, "/", ".", ":", "_" and "-".'), error_message))
+			return
+		return value
+
+
 class Instance(Base):
 
 	def init(self):
@@ -88,22 +102,24 @@ def is_readonly(self, key):
 			return var.get('readonly') in ('yes', '1', 'true')
 		return False
 
+	@sanitize(DictSanitizer({
+		'object': DictSanitizer({
+			'key': UCRKeySanitizer(required=True),
+			'value': StringSanitizer(default=''),
+		})
+	}))
 	def add(self, request):
 		# does the same as put
 		ucr.load()
 		already_set = set(ucr.keys()) & set(v['object']['key'] for v in request.options)
 		if already_set:
-			raise UMC_Error(_('The UCR variable %r is already set.') % (', '.join(already_set)))
+			raise UMC_Error(_('The UCR variable %s is already set.') % ('", "'.join(already_set)))
 
 		self.put(request)
 
-	@simple_response
-	def validate(self, key):
-		return validate_key(key)
-
 	@sanitize(DictSanitizer({
 		'object': DictSanitizer({
-			'key': StringSanitizer(required=True),
+			'key': UCRKeySanitizer(required=True),
 			'value': StringSanitizer(default=''),
 		})
 	}))
@@ -112,8 +128,6 @@ def put(self, request):
 			var = _var['object']
 			value = var['value'] or ''
 			key = var['key']
-			if not validate_key(key):
-				raise UMC_Error(_('The UCR variable %r has an invalid name.') % (key,))
 			if self.is_readonly(key):
 				raise UMC_Error(_('The UCR variable %s is read-only and can not be changed!') % (key,))
 			arg = ['%s=%s' % (key.encode(), value.encode())]
diff --git a/management/univention-management-console-module-ucr/umc/ucr.xml b/management/univention-management-console-module-ucr/umc/ucr.xml
index 3cb3fc4..1975b21 100644
--- a/management/univention-management-console-module-ucr/umc/ucr.xml
+++ b/management/univention-management-console-module-ucr/umc/ucr.xml
@@ -9,7 +9,6 @@
 		</categories>
 		<command name="ucr/put" function="put" />
 		<command name="ucr/add" function="add" />
-		<command name="ucr/validate" function="validate" />
 		<command name="ucr/remove" function="remove" />
 		<command name="ucr/get" function="get" />
 		<command name="ucr/categories" function="categories" />