Loading data distorts form design - wpf

Question

I have a window in wpf that looks like this with no code-behind:
Now that my form looks like I want it to, I use the following to get data from my SQL Server database and load it into the form:
Private Sub winVehicleExpenses_Loaded(sender As Object, e As RoutedEventArgs) Handles winVehicleExpenses.Loaded
taVehicleExpenses = New PIMDataSetTableAdapters.taVehicleExpenses
taVehicleExpenses.Fill(dsPIM.VehicleExpenses) 'Load all the Expense data into the PIM dataset
Dim dvTypes As DataView = New DataView(dsPIM.Tables("StandardEntries"), "CategoryID = 13", "Entry", DataViewRowState.CurrentRows) 'CategoryID = 13 are the Vehicle Expense Types
With cboTypes
.ItemsSource = dvTypes
.SelectedIndex = 0 'Move to the first entry
End With
End Sub
Now when I run the application, here is what the form looks like:
Note the gap between the "Notes" label and the notes textboxes that was not there before the data were loaded.
How can the simple process of loading data into a listbox and some textboxes change the form layout?
ADDED: Here's the XAML
<Window
x:Class="VehicleExpenses"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="VehicleExpense"
xmlns:local="clr-namespace:PIM"
x:Name="winVehicleExpenses"
Height="490"
Width="440"
ShowInTaskbar="False"
Background="#FFE8FFFD"
IsTabStop="False">
<Window.Resources>
<local:DisplayDateFormatter x:Key="FormatDisplayDate" />
<local:DisplayCurrencyFormatter x:Key="FormatCurrency" />
<local:DisplayFixedFormatter x:Key="FormatSingle" />
<Style x:Key="ItemHeaders" TargetType="Label">
<Setter Property="FontWeight" Value="Bold" />
<Setter Property="HorizontalContentAlignment" Value="Center" />
<Setter Property="Grid.Row" Value="1" />
<Setter Property="HorizontalAlignment" Value="Left" />
<Setter Property="VerticalAlignment" Value="Bottom" />
</Style>
<Style x:Key="ItemLabels" TargetType="Label">
<Setter Property="FontWeight" Value="Bold" />
<Setter Property="HorizontalContentAlignment" Value="Right" />
<Setter Property="Height" Value="26" />
<Setter Property="VerticalContentAlignment" Value="Center"/>
<Setter Property="Width" Value="80" />
<Setter Property="Margin" Value="0,5,0,0" />
</Style>
<Style x:Key="PreviousTextBoxes" TargetType="TextBox">
<Setter Property="Height" Value="26" />
<Setter Property="Margin" Value="0,5,0,0" />
<Setter Property="HorizontalAlignment" Value="Left" />
<Setter Property="Width" Value="80" />
<Setter Property="HorizontalContentAlignment" Value="Center" />
<Setter Property="VerticalContentAlignment" Value="Center"/>
<Setter Property="Background" Value="Cornsilk" />
</Style>
<Style TargetType="Button">
<Setter Property="Height" Value="26" />
<Setter Property="Width" Value="60" />
<Setter Property="Margin" Value="60,0,0,0" />
<Setter Property="FontWeight" Value="Bold" />
</Style>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="40" />
<RowDefinition Height="30" />
<RowDefinition Height="225" />
<RowDefinition Height="100" />
<RowDefinition />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="90"/>
<ColumnDefinition />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<StackPanel
Grid.Column="0"
Grid.Row="0"
Grid.ColumnSpan="3"
Orientation="Horizontal"
HorizontalAlignment="Center">
<Label
Height="26"
FontWeight="Bold"
Content="Expense Type:" />
<ComboBox
Name="cboTypes"
Height="26"
Width="120"
FontSize="13"
DisplayMemberPath="Entry"
SelectedValuePath="EntryID"
Background="White" />
</StackPanel>
<Label
Grid.Column="0"
Content="Item"
Width="80"
Style="{StaticResource ItemHeaders}" />
<StackPanel
Grid.Column="0"
Grid.Row="2"
Height="220"
VerticalAlignment="Top">
<Label
Name="lblChargeDate"
Content="Charge Date:"
Style="{StaticResource ItemLabels}" />
<Label
Name="lblMileage"
Content="Mileage:"
Style="{StaticResource ItemLabels}" />
<Label
Name="lblGallons"
Content="Gallons:"
Style="{StaticResource ItemLabels}" />
<Label
Name="lblCharge"
Content="Charge:"
Style="{StaticResource ItemLabels}" />
<Label
Name="lblStartDate"
Content="Start Date:"
Style="{StaticResource ItemLabels}" />
<Label
Name="lblEndDate"
Content="End Date:"
Style="{StaticResource ItemLabels}" />
</StackPanel>
<Label
Content="Previous"
Grid.Column="1"
Width="93"
Style="{StaticResource ItemHeaders}" />
<Label
Content="Current"
Grid.Column="2"
Width="93"
Style="{StaticResource ItemHeaders}" />
<StackPanel
Name="pnlPrevious"
Grid.Column="1"
Grid.Row="2"
Height="220"
VerticalAlignment="Top">
<TextBox
Text="{Binding Path=ChargeDate, Converter={StaticResource FormatDisplayDate}}"
Style="{StaticResource PreviousTextBoxes}"
Focusable="False" />
<TextBox
Name="txtPreviousMileage"
Text="{Binding Path=Mileage}"
Style="{StaticResource PreviousTextBoxes}"
Focusable="False" />
<TextBox
Name="txtPreviousGallons"
Text="{Binding Path=Gallons, Converter={StaticResource FormatSingle}, ConverterParameter=3}"
Style="{StaticResource PreviousTextBoxes}"
Focusable="False" />
<TextBox
Text="{Binding Path=Charge, Converter={StaticResource FormatCurrency}}"
Style="{StaticResource PreviousTextBoxes}"
Focusable="False" />
<TextBox
Name="txtPreviousStartDate"
Text="{Binding Path=StartDate, Converter={StaticResource FormatDisplayDate}}"
Style="{StaticResource PreviousTextBoxes}"
Focusable="False" />
<TextBox
Name="txtPreviousEndDate"
Text="{Binding Path=EndDate, Converter={StaticResource FormatDisplayDate}}"
Style="{StaticResource PreviousTextBoxes}"
Focusable="False" />
<Label
Name="lblNotes"
Content="Notes:"
HorizontalAlignment="Right"
VerticalAlignment="Bottom"
Margin="0,0,30,0"
Style="{StaticResource ItemLabels}" />
</StackPanel>
<StackPanel
Grid.Column="2"
Grid.Row="2"
Height="220"
VerticalAlignment="Top">
<DatePicker
Name="dprCurrentChargeDate"
HorizontalAlignment="Left"
Height="23"
VerticalAlignment="Top"
Width="120" />
<TextBox
Name="txtCurrentMileage"
HorizontalAlignment="Left"
Height="23"
VerticalAlignment="Top"
Width="120" />
<TextBox
Name="txtCurrentsGallons"
HorizontalAlignment="Left"
Height="23"
VerticalAlignment="Top"
Width="120" />
<TextBox
Name="txtCurrentCharge"
HorizontalAlignment="Left"
Height="23"
VerticalAlignment="Top"
Width="120" />
<DatePicker
Name="dprCurrentStartDate"
HorizontalAlignment="Left"
Height="23"
VerticalAlignment="Top"
Width="120" />
<DatePicker
Name="dprCurrentEndDate"
HorizontalAlignment="Left"
Height="23"
VerticalAlignment="Top"
Width="120" />
</StackPanel>
<StackPanel
Grid.Column="0"
Grid.ColumnSpan="3"
Grid.Row="3"
VerticalAlignment="Stretch"
HorizontalAlignment="Stretch"
Orientation="Horizontal">
<TextBox
Name="txtPreviousNotes"
VerticalAlignment="Stretch"
Width="175"
Text="{Binding Notes}"
Background="Cornsilk"
Focusable="False"
Margin="10,0,0,0"/>
<TextBox
Name="txtCurrentNotes"
VerticalAlignment="Stretch"
Width="175"
Margin="55,0,0,0" />
</StackPanel>
<StackPanel
Grid.Column="0"
Grid.Row="4"
Grid.ColumnSpan="3"
Orientation="Horizontal">
<Button
Name="btnCancel"
Content="Cancel"
IsTabStop="False" />
<Button
Name="btnClose"
Content="Close"
IsTabStop="False" />
<Button
Name="btnView"
Content="View"
IsTabStop="False" />
</StackPanel>
</Grid>

Answer 1

Well, after you posted your code and explained further what you're doing, it's pretty clear what's going on. Label lblNotes is in the pnlPrevious StackPanel, which has its VerticalAlignment property set to Top. It makes no difference that you set the VerticalAlignment in the Label to Bottom, since it's a relative property, which makes little difference in a StackPanel. So, when you collapse some of your controls, the content in the pnlPrevious StackPanel rearranges and occupies only as much space as it needs.
The only way to get content to align to the bottom of the StackPanel, without inserting other panels in it, is to align the StackPanel itself to the Bottom. However, that would be a poor decision for your layout.
To save yourself headache and frustration, move lblNotes out of pnlPrevious and into its own row, just above the StackPanel containing notes textboxes.

Answer 2

There a many ways to create the LayOut in XAML.
Without the actual XAML it is a guessing exercition on how the Lay Out changed.