Note: I read over this question and its answers: HorizontalAlignment=Stretch, MaxWidth, and Left aligned at the same time?. None of them do what I am looking for.
I have the following xaml:
<Grid ShowGridLines="True" x:Name="_testGrid" Height="30" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<TextBox Text="Text 1" HorizontalAlignment="Stretch"
MaxWidth="75" Margin="5"/>
<TextBox Grid.Column="1" Text="Text 2" Margin="5"
HorizontalAlignment="Stretch" MaxWidth="130"/>
<TextBox Grid.Column="2" Text="Text 3" Margin="5"
HorizontalAlignment="Stretch" MaxWidth="100"/>
</Grid>
It produces this:

This setup has great resizing support. If the window shrinks then the TextBoxes will shrink too.
The only problem is I need them left aligned:

All the solutions I see end up chopping off part of the textbox (not shrinking it).
Is what I am looking for possible with WPF?
Found an answer here.
It works only with a grid. Here is the updated xaml: