title: WPF GridSplitter with multiple siblings not doen't work as expected
body: <p>I searched around and didn't find similar question on the forum. I have the following WPF code.</p>
  
  <pre><code>&lt;Window x:Class="WpfApp5.MainWindow"
          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:WpfApp5"
          mc:Ignorable="d"
          Title="MainWindow" Height="238.788" Width="406.407"&gt;
      &lt;Grid&gt;
          &lt;Grid.RowDefinitions&gt;
              &lt;RowDefinition Height="*"/&gt;
              &lt;RowDefinition Height="Auto"/&gt;
              &lt;RowDefinition Height="Auto"/&gt;
              &lt;RowDefinition Height="*"/&gt;
          &lt;/Grid.RowDefinitions&gt;
          &lt;TextBox TextWrapping="Wrap" Text="TextBox1 should be resized while moving the GridSplitter"/&gt;
          &lt;GridSplitter HorizontalAlignment="Stretch" Height="5"  Grid.Row="1" /&gt;
          &lt;StackPanel Grid.Row="2" Orientation="Horizontal" Background="Black"&gt;
              &lt;TextBlock Padding="5" Text="I want this black section have fixed height while moving the GridSplitter" Foreground="Aqua" VerticalAlignment="Center" /&gt;
          &lt;/StackPanel&gt;
          &lt;TextBox Grid.Row="3" TextWrapping="Wrap" Text="TextBox2 should be resized while moving the GridSplitter"/&gt;
      &lt;/Grid&gt;
  &lt;/Window&gt;
  </code></pre>
  
  <p>When the user drags the grid splitter, only the two textbox should be resized. But what I got is like this:</p>
  
  <p><a href="https://i.stack.imgur.com/Kv2NF.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Kv2NF.gif" alt="enter image description here"></a></p>
  
  <p>How can I fix this?</p>