diff --git a/common/wx_unit_binder.cpp b/common/wx_unit_binder.cpp
index 9498d3a232..25ef4cb205 100644
--- a/common/wx_unit_binder.cpp
+++ b/common/wx_unit_binder.cpp
@@ -35,7 +35,7 @@
 
 #include "wx_unit_binder.h"
 
-WX_UNIT_BINDER::WX_UNIT_BINDER( wxWindow* aParent, wxTextCtrl* aTextInput, 
+WX_UNIT_BINDER::WX_UNIT_BINDER( wxWindow* aParent, wxTextCtrl* aTextInput,
                                 wxStaticText* aUnitLabel, wxSpinButton* aSpinButton ) :
     m_textCtrl( aTextInput ),
     m_unitLabel( aUnitLabel ),
@@ -60,7 +60,7 @@ void WX_UNIT_BINDER::SetValue( int aValue )
     wxString s = StringFromValue( m_units, aValue, false );
 
     m_textCtrl->SetValue( s );
-    
+
     m_unitLabel->SetLabel( GetAbbreviatedUnitsLabel( m_units ) );
 }
 
@@ -73,6 +73,14 @@ int WX_UNIT_BINDER::GetValue() const
 }
 
 
+bool WX_UNIT_BINDER::Valid() const
+{
+    double dummy;
+
+    return m_textCtrl->GetValue().ToDouble( &dummy );
+}
+
+
 void WX_UNIT_BINDER::Enable( bool aEnable )
 {
     m_textCtrl->Enable( aEnable );
diff --git a/include/wx_unit_binder.h b/include/wx_unit_binder.h
index be4e39d39d..ad4741d563 100644
--- a/include/wx_unit_binder.h
+++ b/include/wx_unit_binder.h
@@ -60,6 +60,12 @@ public:
      */
     virtual int GetValue() const;
 
+    /**
+     * Function Valid
+     * Returns true if the text control contains a real number.
+     */
+    bool Valid() const;
+
     /**
      * Function Enable
      * Enables/diasables the binded widgets