WPF - Weird scrollbars behavior in TabItem

Question

I have following code:

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="145" Width="156">
    <Window.Resources>
        <DataTemplate x:Key="tabTemplate">
            <ScrollViewer>
                <StackPanel Orientation="Vertical">
                    <TextBlock>x</TextBlock>
                    <TextBlock>x</TextBlock>
                    <TextBlock>x</TextBlock>
                    <TextBlock>x</TextBlock>
                    <TextBlock>x</TextBlock>
                    <TextBlock>x</TextBlock>
                    <TextBlock>x</TextBlock>
                </StackPanel>
            </ScrollViewer>
        </DataTemplate>
    </Window.Resources>
    <Grid>
        <TabControl>
            <TabItem Header="Tab1" ContentTemplate="{StaticResource ResourceKey=tabTemplate}"/>
            <TabItem Header="Tab2" ContentTemplate="{StaticResource ResourceKey=tabTemplate}"/>
        </TabControl>
    </Grid>
</Window>

What is weird is the behavior of scrollbars - if I scroll down on the first tab and switch to second tab, the scrollbar is down too - position of the scrollbars is synchronized when the tab items have the same data templates. Do you know about any solution of this issue?

In addition, when I alter the code and make two data templates (one for each tab), the scrollbars are not preserving their position at all - that means if I scroll down on tab1, switch to tab2 and to tab1 again, the scrollbar is on default position. Any solution of this one?

Answer 1

To enable the DataTemplate to create separate instances for each usage, just set the x:Shared attribute to False:

<DataTemplate x:Key="tabTemplate" x:Shared="False">

That will cause your second issue, which is preserving the UI when the tab changes. According to http://stackoverflow.com/questions/2082331, the solution would be to use a different ItemsControl that looks like a TabControl.