diff --git a/CPF/Controls/TextBlock.cs b/CPF/Controls/TextBlock.cs
index 433739ab4ef571b36c302cd83959060d4dd6c031..996c79d2ffb6a4f70e753e94f2b3ceb00fb49ad3 100644
--- a/CPF/Controls/TextBlock.cs
+++ b/CPF/Controls/TextBlock.cs
@@ -282,6 +282,7 @@ namespace CPF.Controls
             }
             else
             {
+                textSize = new Size();
                 return base.ArrangeOverride(finalSize);
             }
         }