diff --git a/src/Umbraco.Web.UI/umbraco/dialogs/AssignDomain2.aspx b/src/Umbraco.Web.UI/umbraco/dialogs/AssignDomain2.aspx
index 2464e9446b..9a69576706 100644
--- a/src/Umbraco.Web.UI/umbraco/dialogs/AssignDomain2.aspx
+++ b/src/Umbraco.Web.UI/umbraco/dialogs/AssignDomain2.aspx
@@ -51,7 +51,7 @@
                     </thead>
                     <tbody data-bind="foreach: domains">
                         <tr>
-                            <td valign="top"><input class="domain" data-bind="value: Name, uniqueName: true"  /><input type="hidden" value="0" /></td>
+                            <td valign="top"><input class="domain" data-bind="value: Name, uniqueName: true"  /><input type="hidden" value="0" data-bind="uniqueName: true"/></td>
                             <td valign="top"><select class="language" data-bind="options: $parent.languages, optionsText: 'Code', optionsValue: 'Id', value: Lang, uniqueName: true"></select></td>
                             <td valign="top"><a href="#" class="btn btn-danger" data-bind="click: $parent.removeDomain"><i class="icon icon-trash"></i></a></td>
                         </tr>
diff --git a/src/Umbraco.Web.UI/umbraco_client/Dialogs/AssignDomain2.js b/src/Umbraco.Web.UI/umbraco_client/Dialogs/AssignDomain2.js
index 92cb1b50a9..cfd33541cb 100644
--- a/src/Umbraco.Web.UI/umbraco_client/Dialogs/AssignDomain2.js
+++ b/src/Umbraco.Web.UI/umbraco_client/Dialogs/AssignDomain2.js
@@ -52,9 +52,15 @@
             ko.applyBindings(self);
 
             $.validator.addMethod("domain", function (value, element, param) {
+                // beware! encode('test') == 'test-'
+                // read eg https://rt.cpan.org/Public/Bug/Display.html?id=94347
                 value = punycode.encode(value);
-                var re = /^(http[s]?:\/\/)?([-\w]+(\.[-\w]+)*)(:\d+)?(\/[-\w]*)?$/gi;
-                return this.optional(element) || re.test(value);
+                // that regex is best-effort and certainly not exact
+                var re = /^(http[s]?:\/\/)?([-\w]+(\.[-\w]+)*)(:\d+)?(\/[-\w]*|-)?$/gi;
+                var isopt = this.optional(element);
+                var retest = re.test(value);
+                var ret = isopt || retest;
+                return ret;
             }, self._opts.invalidDomain);
 
             $.validator.addMethod("duplicate", function (value, element, param) {
@@ -85,7 +91,7 @@
                     return false;
                 
                 var mask = $('#komask');
-                var masked = mask.next();
+                var masked = mask.parent();
                 mask.height(masked.height());
                 mask.width(masked.width());
                 mask.show();
diff --git a/src/Umbraco.Web/umbraco.presentation/umbraco/dialogs/AssignDomain2.aspx b/src/Umbraco.Web/umbraco.presentation/umbraco/dialogs/AssignDomain2.aspx
index ec6e9f7669..88af0c2007 100644
--- a/src/Umbraco.Web/umbraco.presentation/umbraco/dialogs/AssignDomain2.aspx
+++ b/src/Umbraco.Web/umbraco.presentation/umbraco/dialogs/AssignDomain2.aspx
@@ -53,7 +53,7 @@
                     <tbody data-bind="foreach: domains">
                         <tr>
                             <td valign="top">
-                                <input class="domain" data-bind="value: Name, uniqueName: true" /><input type="hidden" value="0" /></td>
+                                <input class="domain" data-bind="value: Name, uniqueName: true" /><input type="hidden" value="0" data-bind="uniqueName: true"/></td>
                             <td valign="top">
                                 <select class="language" data-bind="options: $parent.languages, optionsText: 'Code', optionsValue: 'Id', value: Lang, uniqueName: true"></select></td>
                             <td valign="top"><a href="#" class="btn btn-danger" data-bind="click: $parent.removeDomain"><i class="icon icon-trash"></i></a></td>