WPF Grid SharedSizeGroup Error

Question

If you run this code and click on tab 2, and then on tab 1, the application will go crazy and will start to bounce column widths back and forth. Any suggestions on how to fix this?

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow"
    Height="350"
    Width="525">
<Grid IsSharedSizeScope="True">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto" />
        <ColumnDefinition Width="*" />
        <ColumnDefinition Width="Auto"
                          SharedSizeGroup="Col3" />
        <ColumnDefinition Width="*" />
    </Grid.ColumnDefinitions>

    <TextBlock Text="Label 1"
               Grid.Row="0"
               Grid.Column="0" />

    <TextBox Grid.Column="1"
             Grid.Row="0"
             Text="TextBox 1" />

    <TextBlock Text="Label 2"
               Grid.Row="0"
               Grid.Column="2" />

    <TextBox Grid.Column="3"
             Grid.Row="0"
             Text="TextBox 2" />

    <DockPanel Grid.Row="1"
               Grid.Column="2"
               Grid.ColumnSpan="2">

        <TabControl>
            <TabItem Header="Tab 1">
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition SharedSizeGroup="Col3" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>
                    <TextBlock Text="Tab 1: Short Text.."
                               Grid.Row="0"
                               Grid.Column="0" />

                </Grid>
            </TabItem>
            <TabItem Header="Tab 2">
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition SharedSizeGroup="Col3" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>
                    <TextBlock Text="Tab 2: Short Text.."
                               Grid.Row="0"
                               Grid.Column="0" />
                    <TextBlock Text="Tab 2: Long Text..................................... "
                               Grid.Row="1"
                               Grid.Column="0" />
                </Grid>
            </TabItem>
        </TabControl>
    </DockPanel>
    </Grid>
</Window>

This is removed from a similar application and greatly simplified. The root of the problem is the SharedSizeGroup "Col3". There are other elements in the actual application that share this column, so I cannot remove the SharedSizeGroup if there is no other way to accomplish the desired behavior.

Answer 1

Grid.IsSharedSizeScope True (TabControl) . :

<TabControl Grid.IsSharedSizeScope="True">

TabControl .