How do I implement WPF group box than spans two columns?
Here is the layout I want:

Grid with 2 columns, 2 rows

Row 1 should contain a group box that spans both columns.
Row 2, Column 1 will contain a group box
Row 2, Column 2 will contain another group box.

In row 1's group box, I want the left side to have a stack of labels/combo boxes.  On the right side will be a stack of labels/checkboxes.  In the Row 2/Column 1 group box, I want more labels/combo boxes that should align with the first row's labels/combo boxes.  In the Row 2/Column 2 group box, I want more labels/checkboxes that align with the first row's labels/checkboxes.

Here is what I have so far.  The problem I'm having is that the label/combo box pairs in row 1's group box want to span the entire group box.  But, I am explicitly setting the row=0, column=0 for the inner grid that contains the labels/combo boxes.

Forgive me if this doesn't compile as I'm typing from a printout on a computer without Studio.

    <Grid>
       <Grid.RowDefinitions>
          <RowDefinition/>
          <RowDefinition/>      
       </Grid.RowDefinitions>
       <Grid.ColumnDefinitions>
          <ColumnDefinition/>
          <ColumnDefinition/>
       <Grid.ColumnDefinitions>
       <GroupBox Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2">
          <GroupBox.Header>
             <Label Content="Device Configuration"></Label>
          </GroupBox.Header>
          <Grid Grid.Row="0" Column="0">
             <Grid.RowDefinitions>
                <RowDefinition/>
                <RowDefinition/>      
                <RowDefinition/>      
             </Grid.RowDefinitions>
             <Grid.ColumnDefinitions>
                <ColumnDefinition/>
                <ColumnDefinition/>
             <Grid.ColumnDefinitions>
    
             <Label Grid.Column="0" Grid.Row="0" Content="Label 1"></Label>
             <ComboBox Grid.Column="1" Grid.Row="0"></ComboBox>
    
             <Label Grid.Column="0" Grid.Row="1" Content="Label 2"></Label>
             <ComboBox Grid.Column="1" Grid.Row="1"></ComboBox>
    
             <Label Grid.Column="0" Grid.Row="2" Content="Label 3"></Label>
             <ComboBox Grid.Column="1" Grid.Row="2"></ComboBox>
          </Grid>
       </GroupBox>
    </Grid>
How do I implement WPF group box than spans two columns?
===

Here is the layout I want:

Grid with 2 columns, 2 rows

Row 1 should contain a group box that spans both columns.
Row 2, Column 1 will contain a group box
Row 2, Column 2 will contain another group box.

In row 1's group box, I want the left side to have a stack of labels/combo boxes.  On the right side will be a stack of labels/checkboxes.  In the Row 2/Column 1 group box, I want more labels/combo boxes that should align with the first row's labels/combo boxes.  In the Row 2/Column 2 group box, I want more labels/checkboxes that align with the first row's labels/checkboxes.

Here is what I have so far.  The problem I'm having is that the label/combo box pairs in row 1's group box want to span the entire group box.  But, I am explicitly setting the row=0, column=0 for the inner grid that contains the labels/combo boxes.

Forgive me if this doesn't compile as I'm typing from a printout on a computer without Studio.

    <Grid>
       <Grid.RowDefinitions>
          <RowDefinition/>
          <RowDefinition/>      
       </Grid.RowDefinitions>
       <Grid.ColumnDefinitions>
          <ColumnDefinition/>
          <ColumnDefinition/>
       <Grid.ColumnDefinitions>
       <GroupBox Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2">
          <GroupBox.Header>
             <Label Content="Device Configuration"></Label>
          </GroupBox.Header>
          <Grid Grid.Row="0" Column="0">
             <Grid.RowDefinitions>
                <RowDefinition/>
                <RowDefinition/>      
                <RowDefinition/>      
             </Grid.RowDefinitions>
             <Grid.ColumnDefinitions>
                <ColumnDefinition/>
                <ColumnDefinition/>
             <Grid.ColumnDefinitions>
    
             <Label Grid.Column="0" Grid.Row="0" Content="Label 1"></Label>
             <ComboBox Grid.Column="1" Grid.Row="0"></ComboBox>
    
             <Label Grid.Column="0" Grid.Row="1" Content="Label 2"></Label>
             <ComboBox Grid.Column="1" Grid.Row="1"></ComboBox>
    
             <Label Grid.Column="0" Grid.Row="2" Content="Label 3"></Label>
             <ComboBox Grid.Column="1" Grid.Row="2"></ComboBox>
          </Grid>
       </GroupBox>
    </Grid>