Display access key in ControlCatalog pages.

samples/ControlCatalog/Pages/CheckBoxPage.xaml

@@ -11,9 +11,9 @@
                 Spacing="16">
       <StackPanel Orientation="Vertical"
                   Spacing="16">
-        <CheckBox>Unchecked</CheckBox>
-        <CheckBox IsChecked="True">Checked</CheckBox>
-        <CheckBox IsChecked="{x:Null}">Indeterminate</CheckBox>
+        <CheckBox>_Unchecked</CheckBox>
+        <CheckBox IsChecked="True">_Checked</CheckBox>
+        <CheckBox IsChecked="{x:Null}">_Indeterminate</CheckBox>
         <CheckBox IsChecked="True" IsEnabled="False">Disabled</CheckBox>
       </StackPanel>
       <StackPanel Orientation="Vertical"

samples/ControlCatalog/Pages/DialogsPage.xaml

@@ -3,15 +3,15 @@
              x:Class="ControlCatalog.Pages.DialogsPage">
   <StackPanel Orientation="Vertical" Spacing="4" Margin="4">
       <CheckBox Name="UseFilters">Use filters</CheckBox>
-      <Button Name="OpenFile">Open File</Button>
-      <Button Name="SaveFile">Save File</Button>
-      <Button Name="SelectFolder">Select Folder</Button>
-      <Button Name="OpenBoth">Select Both</Button>
-      <Button Name="DecoratedWindow">Decorated window</Button>
-      <Button Name="DecoratedWindowDialog">Decorated window (dialog)</Button>
-      <Button Name="Dialog">Dialog</Button>
-      <Button Name="DialogNoTaskbar">Dialog (No taskbar icon)</Button>
-      <Button Name="OwnedWindow">Owned window</Button>
-      <Button Name="OwnedWindowNoTaskbar">Owned window (No taskbar icon)</Button>
+      <Button Name="OpenFile">_Open File</Button>
+      <Button Name="SaveFile">_Save File</Button>
+      <Button Name="SelectFolder">Select Fo_lder</Button>
+      <Button Name="OpenBoth">Select _Both</Button>
+      <Button Name="DecoratedWindow">Decorated _window</Button>
+      <Button Name="DecoratedWindowDialog">Decorated w_indow (dialog)</Button>
+      <Button Name="Dialog">_Dialog</Button>
+      <Button Name="DialogNoTaskbar">Dialog (_No taskbar icon)</Button>
+      <Button Name="OwnedWindow">Own_ed window</Button>
+      <Button Name="OwnedWindowNoTaskbar">Owned window (No tas_kbar icon)</Button>
   </StackPanel>
 </UserControl>