Created Unassigned: AvalonDock LayoutPanes never show scrollbars inside [22058]

I have several toolwindows added to my dockingmanager in an mvvm application. Even if the usercontrol used to template the toolwindow defines scrolling, minsize, etc. there ain't ever scrollbars showed.

```
<UserControl MinHeight="100" MinWidth="200" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch"
ScrollViewer.CanContentScroll="True" ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="">
<Grid>
...some content
<Grid>
</UserControl>
```

I also tried setting these on my datatemplate:
```
<xcad:DockingManager.LayoutItemTemplateSelector>
<helper:PanesTemplateSelector>
<helper:PanesTemplateSelector.QueryViewTemplate>
<DataTemplate>
<view:QueryView MinHeight="100" MinWidth="200" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" ScrollViewer.CanContentScroll="True" ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto" />
</DataTemplate>
</helper:PanesTemplateSelector.QueryViewTemplate>
```

Even worse it seems MinWidth and MinHeight are totally ignored. In float mode only it seems MinWidth is respected.