title: how to add a multiple buttons inside a groupbox in wpf?
body: <p>I need to add a multiple buttons inside a groupbox in wpf, but I can't. I need to create my key pad for an atm machine, with all numbers, but if I try to create a button number 2, the button number 1 disappears.
  what is wrong?  </p>
  
  <pre><code>&lt;Window x:Name="Win_Users" x:Class="ATM_Simulator.WindowUsers"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      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:local="clr-namespace:ATM_Simulator"
      mc:Ignorable="d"
      Title="WindowUsers" Height="300" Width="500"&gt;
  &lt;Grid&gt;
      &lt;GroupBox x:Name="grbx_key_pad" Header="Key Pad" HorizontalAlignment="Left" Height="220" Margin="26,10,0,0" VerticalAlignment="Top" Width="189"&gt;
          &lt;Button x:Name="btn_1" Content="1" HorizontalAlignment="Left" Margin="10,13,0,0" VerticalAlignment="Top" Width="29" Height="32"/&gt;
      &lt;/GroupBox&gt;
      &lt;GroupBox x:Name="grbx_select_transaction" Header="Select Transaction :" HorizontalAlignment="Left" Height="88" Margin="291,23,0,0" VerticalAlignment="Top" Width="179"/&gt;
      &lt;GroupBox x:Name="grbx_select_account" Header="Select Account" HorizontalAlignment="Left" Height="92" Margin="291,138,0,0" VerticalAlignment="Top" Width="179"/&gt;
      &lt;Button x:Name="btn_submit" Content="Submit" HorizontalAlignment="Left" Margin="291,239,0,0" VerticalAlignment="Top" Width="75"/&gt;
      &lt;Button x:Name="btn_close" Content="Close" HorizontalAlignment="Left" Margin="393,239,0,0" VerticalAlignment="Top" Width="77"/&gt;
  &lt;/Grid&gt;
  </code></pre>
  
  <p></p>