Making a visible/invisible panel that resizes the main window - wpf

Question

I wish to achieve an effect like common media players with an eq or tracklist panel that can be shown or less with a click.
The main window should so automatically resize with the displayed content.
I wonder if I must care to do manually specifing the size or there's a solution more clear.
<Window x:Class="WpfApplicationAnimation.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="Auto" Width="Auto" SizeToContent="WidthAndHeight">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<Label Margin="5" Grid.Column="0" Grid.Row="0">Value 1:</Label>
<Label Margin="5" Grid.Column="0" Grid.Row="1">Value 2:</Label>
<Label Margin="5" Grid.Column="0" Grid.Row="2">Value 3:</Label>
<Button Margin="5" Click="Button_Click_1" Grid.Column="0" Grid.Row="3" Visibility="Hidden">Hello</Button>
<TextBox Name="txt1" Margin="5" Grid.Column="1" Grid.Row="0" MinWidth="100" />
<TextBox Margin="5" Grid.Column="1" Grid.Row="1" MinWidth="100" />
<TextBox Margin="5" Grid.Column="1" Grid.Row="2" MinWidth="100" />
</Grid>
I tried with setting SizeToContent="WidthAndHeight" but even if visible the content of the button take the required space.

Answer 1

You can try to use an Expander although will not be the same effect. The problem will be Window Transparency (so you can get a rid out of that, as Winamp does; but then you get into a Memory Leak). But, expander is the only control I know that enables to to that automatically. Sure, you can always arrange and resize manually, but that's what you're trying to avoid.