remove accidentally pasted code.

samples/ControlCatalog/MainView.xaml

@@ -31,7 +31,6 @@
       <TabItem Header="Menu"><pages:MenuPage/></TabItem>
       <TabItem Header="Notifications"><pages:NotificationsPage/></TabItem>
 	  <TabItem Header="NumericUpDown"><pages:NumericUpDownPage/></TabItem>
-	  <TabItem Header="NumericUpDown"><pages:NumericUpDownPage/></TabItem>
       <TabItem Header="ProgressBar"><pages:ProgressBarPage/></TabItem>
       <TabItem Header="RadioButton"><pages:RadioButtonPage/></TabItem>
       <TabItem Header="Slider"><pages:SliderPage/></TabItem>