diff --git a/ide/outputfilter.pas b/ide/outputfilter.pas
index 6e8c229946..6b871d9e18 100644
--- a/ide/outputfilter.pas
+++ b/ide/outputfilter.pas
@@ -92,6 +92,7 @@ type
   }
   TOutputLines = class(TStringList)
   public
+    destructor Destroy; override;
     procedure Clear; override;
     procedure Delete(Index: Integer); override;
   end;
@@ -1034,6 +1035,12 @@ end;
 
 { TOutputLines }
 
+destructor TOutputLines.Destroy;
+begin
+  Clear; // To free the associated objects
+  inherited Destroy;
+end;
+
 procedure TOutputLines.Clear;
 var
   i: Integer;