diff --git a/TestSuite/extensionmethods33.pas b/TestSuite/extensionmethods33.pas
new file mode 100644
index 000000000..71edae23f
--- /dev/null
+++ b/TestSuite/extensionmethods33.pas
@@ -0,0 +1,30 @@
+uses System.Windows.Forms;
+{$reference System.Windows.Forms.dll}
+
+var i: integer;
+
+procedure p1(self: Control); extensionmethod;
+begin
+  Inc(i);
+end;
+
+type
+  
+  t1 = abstract class(Panel)
+    
+  end;
+  
+  t2 = sealed class(t1)
+    
+    constructor;
+    begin
+      t1(self).p1;
+      self.p1;
+    end;
+    
+  end;
+  
+begin 
+  var o := new t2;
+  assert(i = 2);
+end.
\ No newline at end of file
diff --git a/TreeConverter/TreeRealization/types.cs b/TreeConverter/TreeRealization/types.cs
index 954ff4fa1..ce0f63bed 100644
--- a/TreeConverter/TreeRealization/types.cs
+++ b/TreeConverter/TreeRealization/types.cs
@@ -2041,12 +2041,18 @@ namespace PascalABCCompiler.TreeRealization
                 //sil = (base_type as compiled_generic_instance_type_node).original_generic.find_in_type(name, CurrentScope);
                 return sil;
             }
-                
 
-            if (sil == null && base_type is compiled_type_node && string.Compare(name, "create", true) != 0)
+            type_node base_tn = base_type;
+            if (sil == null && string.Compare(name, "create", true) != 0)
             {
-                sil = (base_type as compiled_type_node).find_in_type(name, CurrentScope);
+                while (sil == null && base_tn != null)
+                {
+                    if (base_tn is compiled_type_node)
+                        sil = (base_tn as compiled_type_node).find_in_type(name, CurrentScope);
+                    base_tn = base_tn.base_type;
+                }
             }
+            
             if (this.is_generic_parameter && sil != null)
             {
                 sil = sil?.Select(x => x.copy()).ToList();