Adding test and update render to fix issue with rendering separator when headers are hidden fixing issue 1391.

src/Spectre.Console/Widgets/Table/TableRenderer.cs

@@ -150,9 +150,9 @@ internal static class TableRenderer
                 result.Add(Segment.LineBreak);
             }
 
-            // Show row separator?
+            // Show row separator, if headers are hidden show separator after the first row
             if (context.Border.SupportsRowSeparator && context.ShowRowSeparators
-                                                    && !isFirstRow && !isLastRow)
+                                                    && (!isFirstRow || (isFirstRow && !context.ShowHeaders)) && !isLastRow)
             {
                 var hasVisibleFootes = context is { ShowFooters: true, HasFooters: true };
                 var isNextLastLine = index == context.Rows.Count - 2;

test/Spectre.Console.Tests/Expectations/Widgets/Table/Render_Row_Separators_No_Header.Output.verified.txt

@@ -0,0 +1,7 @@
+┌────────┬────────┐
+│ Qux    │ Corgi  │
+├────────┼────────┤
+│ Waldo  │ Grault │
+├────────┼────────┤
+│ Garply │ Fred   │
+└────────┴────────┘

test/Spectre.Console.Tests/Unit/Widgets/Table/TableTests.cs

@@ -159,6 +159,29 @@ public sealed class TableTests
         return Verifier.Verify(console.Output);
     }
 
+    [Fact]
+    [Expectation("Render_Row_Separators_No_Header")]
+    public Task Should_Render_Table_With_Row_Separators_No_Header_Correctly()
+    {
+        // Given
+        var console = new TestConsole();
+        var table = new Table();
+
+        table.ShowRowSeparators();
+        table.HideHeaders();
+
+        table.AddColumns("Foo", "Bar");
+        table.AddRow("Qux", "Corgi");
+        table.AddRow("Waldo", "Grault");
+        table.AddRow("Garply", "Fred");
+
+        // When
+        console.Write(table);
+
+        // Then
+        return Verifier.Verify(console.Output);
+    }
+
     [Fact]
     [Expectation("Render_EA_Character")]
     public Task Should_Render_Table_With_EA_Character_Correctly()