Weird binding behavior

Hey guys,

I've got a weird binding behavior in my application.

It's hard to explain so i will try my best by using some pics :-)

I've got an MVVM-based application which contains a shellview (Window) and a subviews (UserControl)

On startup the shellviewmodel creates 2 instances of the subview which were kept in a collection and this one is bound to the Itemsource property of a combobox.

by switching the selection of the combobox the current view of the shellview is changed.


The subview contains the Viewport and a 3D Model.

<HelixViewport3D Grid.Row="1" ZoomExtentsWhenLoaded="True" 
                                   ShowCoordinateSystem="{Binding ElementName=cbxShowDimensions, Path=IsChecked}">
            <SunLight/>
            <ns:Component3D 
                                   Length="2400" 
                                   Width="1800" 
                                   Thickness="25" 
                                   ShowMeasurements="{Binding ElementName=cbxShowDimensions, Path=IsChecked}"/>
            <SunLight/>
</HelixViewport3D>

As you can see the ShowCoordinateSystem-Property of the Viewport and the ShowMeasurements-Property of the 3D-Model are bound to a checkbox

Now the problem:

View one is updating properly




View 2 does not only the coordinate system does.

Missing dimensions :-(