diff --git a/tests/ParserTests/Discussion468/Discussion468Lexer.cs b/tests/ParserTests/Discussion468/Discussion468Lexer.cs
new file mode 100644
index 00000000..2a724d53
--- /dev/null
+++ b/tests/ParserTests/Discussion468/Discussion468Lexer.cs
@@ -0,0 +1,11 @@
+using sly.lexer;
+
+namespace ParserTests.Discussion468
+{
+    public enum Discussion468Lexer
+    {
+        [CustomId("_.:a-zA-Z","_.:0-9a-zA-Z")]
+        INDENTIFIER
+
+    }
+}
\ No newline at end of file
diff --git a/tests/ParserTests/Discussion468/Discussion468Tests.cs b/tests/ParserTests/Discussion468/Discussion468Tests.cs
new file mode 100644
index 00000000..fb74f528
--- /dev/null
+++ b/tests/ParserTests/Discussion468/Discussion468Tests.cs
@@ -0,0 +1,52 @@
+using System.Linq;
+using expressionparser;
+using NFluent;
+using simpleExpressionParser;
+using sly.lexer;
+using sly.parser;
+using sly.parser.generator;
+using Xunit;
+
+namespace ParserTests.Discussion468
+{
+    public class Discussion468Tests
+    {
+
+
+
+        private static void CheckId(ILexer<Discussion468Lexer> lexer,string source, bool isOk)
+        {
+            
+            var lexingResult = lexer.Tokenize(source);
+            if (isOk)
+            {
+                Check.That(lexingResult).IsOkLexing();
+                var tokens = lexingResult.Tokens;
+                Check.That(tokens).IsNotNull();
+                Check.That(tokens).CountIs(2);
+                var idToken = tokens[0];
+                Check.That(idToken.TokenID).IsEqualTo(Discussion468Lexer.INDENTIFIER);
+                Check.That(idToken.Value).IsEqualTo(source);
+            }
+            else
+            {
+                Check.That(lexingResult).Not.IsOkLexing();
+            }
+        }
+
+        [Fact]
+        public static void Test468()
+        {
+            var buildResult = LexerBuilder.BuildLexer<Discussion468Lexer>();
+            Check.That(buildResult).IsOk();
+            var lexer = buildResult.Result;
+            Check.That(lexer).IsNotNull();
+            CheckId(lexer,"_:word1234",true);
+            CheckId(lexer,"word_1234.otherword",true);
+            CheckId(lexer,"1_:word1234",false);
+            
+        }
+        
+       
+    }
+}
\ No newline at end of file