diff --git a/src/Plugin/UiPatterns/Source/AttributesWidget.php b/src/Plugin/UiPatterns/Source/AttributesWidget.php
index 15741cb2617b94c6b637a084f2a0dee7483d1b09..6c0581292be69d16b2663e74686615b1c170bbf5 100644
--- a/src/Plugin/UiPatterns/Source/AttributesWidget.php
+++ b/src/Plugin/UiPatterns/Source/AttributesWidget.php
@@ -63,9 +63,9 @@ class AttributesWidget extends SourcePluginBase {
    */
   protected function buildRegexPattern(): string {
     // Attribute names are a mix of ASCII lower and upper alphas.
-    $attr_name = "[a-zA-Z]+";
+    $attr_name = "[a-zA-Z\-]+";
     // Allow anything in attributes values, which are between double quotes.
-    $double_quoted_value = '"[\s\w]*"';
+    $double_quoted_value = '"[\s\w\-]*"';
     $space = "\s*";
     $attr = $attr_name . "=" . $double_quoted_value . $space;
     // The pattern must match the entire input's value, rather than matching a