built-in WM_APPCOMMAND support

mpv.net/WPF/AboutWindow.xaml

@@ -3,7 +3,7 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
-        xmlns:UI="clr-namespace:UI"
+        xmlns:mpvnet="clr-namespace:mpvnet"
         mc:Ignorable="d"
         
         Title="About mpv.net"
@@ -13,8 +13,8 @@
         ShowInTaskbar="False"
         WindowStartupLocation="CenterOwner"
         ResizeMode="NoResize"
-        Foreground="{x:Static UI:Theme.Foreground}"
-        Background="{x:Static UI:Theme.Background}">
+        Foreground="{x:Static mpvnet:Theme.Foreground}"
+        Background="{x:Static mpvnet:Theme.Background}">
     
     <Grid>
         <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">