diff --git a/components/lazutils/dictionarystringlist.pas b/components/lazutils/dictionarystringlist.pas
index 04b5db7c16..6d88dd1617 100644
--- a/components/lazutils/dictionarystringlist.pas
+++ b/components/lazutils/dictionarystringlist.pas
@@ -53,9 +53,25 @@ type
     function IndexOf(const S: string): Integer; override;
   end;
 
+  procedure Deduplicate(AStrings: TStringList);
 
 implementation
 
+procedure Deduplicate(AStrings: TStringList);
+var
+  DSL :TDictionaryStringList;
+begin
+  if AStrings.OwnsObjects then
+    raise Exception.Create('Deduplicate: OwnsObjects in AStrings is not supported.');
+  DSL := TDictionaryStringList.Create;
+  try
+    DSL.Assign(AStrings);
+    AStrings.Assign(DSL);
+  finally
+    DSL.Free;
+  end;
+end;
+
 { TDictionaryStringList }
 
 constructor TDictionaryStringList.Create;