How to bind the name of the active TabItem to a Label in WPF?

Question

actual the Labels shows the namespace of the control and not the name (header) of the active tabitem.

..
<Label Content="{x:Type TabControl}" />
</Grid>

<TabControl>

    <TabItem Header="Header1" />
    <TabItem Header="Header2" />
    ..

Answer 1

You obviously have no clue about what you are doing, read this: Data Binding Overview
The x:Type markup extension has nothing to do with binding, it just returns the type of a given class.

---

One way to bind to the selected item:

<Label Content="{Binding ElementName=tc, Path=SelectedItem.Header}"/>
<TabControl Name="tc" ...>
     <!-- Items -->
</TabControl>

(Note: The SelectedItem normally (- when using ItemsSource -) does not represent the selected control but the data behind the selected item)