Created Unassigned: Caption Height for Custom Pane Header [17761]

Hi,

I modified _AnchorablePaneControlStyle_ in my _DockManager_ to customize my pane header.
It works and the header is bigger now (like I want, see attached pics).

But there is an issue regarding the header caption area when undocking.
Obviously, the caption area is related to textbox control inside the _AnchorableTitleTemplate_, I mean I can only undock from a position inside text box.
It means if I want to center my textbox (and this is what I want to do, see attached pics), the textbox control is resized and I can t undock from outside textbox area.

I tried to put textbox in a grid modifying _AnchorableTitleTemplate_ but nothings changes.

I modified AnchorableControlStyle to have my custom header

```
<Border Background="WhiteSmoke" Border.Name="Header" Height="48">
<xcad:AnchorablePaneTitle Height="{TemplateBinding Height}" Foreground="Gray" FontSize="22" Style="{StaticResource AnchorablePaneTitleStyle}" Model="{Binding Model,RelativeSource={RelativeSource TemplatedParent}}" xmlns:avalonDockControls="clr-namespace:Xceed.Wpf.AvalonDock.Controls;assembly=Xceed.Wpf.AvalonDock,Version=3.0.16572.0,Culture=neutral,PublicKeyToken=ba83ff368b7563c6" />
</Border>
```

How can I solve that please ?

Thanks in advance
Sebastien