Tweaked validation logic

Terminal.Gui/View/Layout/ViewLayout.cs

@@ -1119,6 +1119,9 @@ public partial class View
 
                     break;
 
+                case Dim dim and DimAuto:
+                    break;
+
                 case Dim dim and not DimAbsolute and not DimView and not DimCombine:
                     bad = dim;
 

UICatalog/Scenarios/MessageBoxes.cs

@@ -190,7 +190,7 @@ public class MessageBoxes : Scenario
         };
         frame.Add (ckbWrapMessage);
 
-        //frame.ValidatePosDim = true;
+        frame.ValidatePosDim = true;
 
         label = new ()
         {