diff --git a/common/widgets/unit_binder.cpp b/common/widgets/unit_binder.cpp
index cd1d42d5f3..d1b858537f 100644
--- a/common/widgets/unit_binder.cpp
+++ b/common/widgets/unit_binder.cpp
@@ -122,7 +122,7 @@ void UNIT_BINDER::onSetFocus( wxFocusEvent& aEvent )
     {
         wxString oldStr = m_eval.OriginalText();
 
-        if( oldStr.length() )
+        if( oldStr.length() && oldStr != textEntry->GetValue() )
         {
             textEntry->SetValue( oldStr );
             textEntry->SetSelection( m_selStart, m_selEnd );