Put resizable Expander to expand from right to left

Question

I would like to have the Expander from question below (see the accepted answer) which is a perfect solution for me. I just want to have it on the right side.

Combine expander and grid (resizable expander)

To have it expanded from right to left I changed the settings for an analoguous behavior. (I emphasized elements to see better what's going on):

<Expander Grid.Column="1" Header="Test" ExpandDirection="Left" 
        BorderThickness="10" BorderBrush="Black" HorizontalAlignment="Right" >
  <Expander.Content>
    <Grid >
       <Grid.ColumnDefinitions>
         <ColumnDefinition Width="Auto"/>
         <ColumnDefinition Width="Auto" />
       </Grid.ColumnDefinitions>
       <GridSplitter Grid.Column="0" Width="10" Background="Green" 
                  ResizeDirection="Columns" ResizeBehavior="CurrentAndNext" />
       <TextBox Grid.Column="1" Text="Lorem ipsum dolor sit" 
             BorderThickness="10" BorderBrush="Red"/>
    </Grid>
  </Expander.Content>
</Expander>

It resizes the area left from the splitter when I move the splitter to the right. I tried many other combinations but it almost resulted in the same unwanted behavior. The area left of the splitter is sometimes kind of weirdly exploding but TextBox remains unchanged.

Answer 1

Try like this:

<Expander Grid.Column="1" Header="Test" ExpandDirection="Left"
    BorderThickness="10" BorderBrush="Black" HorizontalAlignment="Right">
  <Expander.Content>
    <Grid>
       <Grid.ColumnDefinitions>
         <ColumnDefinition Width="*" MinWidth="10" />
         <ColumnDefinition Width="Auto" />
       </Grid.ColumnDefinitions>
       <GridSplitter Grid.Column="0" Width="10" Background="Green"
                  ResizeDirection="Columns" ResizeBehavior="CurrentAndNext" />
       <TextBox Grid.Column="1" Text="Lorem ipsum dolor sit"
             BorderThickness="10" BorderBrush="Red"/>
    </Grid>
  </Expander.Content>
</Expander>