Code shows error Cannot Create Control

DonFreeman

Why is it that this code:

 <Grid Grid.Column="1">
   <tb:dfMapToolbar x:Name="toolbar" 
    tbMap="{Binding ElementName=MyMap}" />
  </Grid>

Works fine on page5 but when placed on page6 it shows and error that simply says "cannot create an instance of dfMapToolbar"? All the headers on the 2 pages are the same. When run the toolbar DOES show up on Page6 and appears active. On a related note, I am trying to build a custom control from the ESRI sample and it seems to work except that zoom functions do not. It seems that after moving the toolbar into a separate control, I lose the mouse down event which starts to draw the zoom rectangle. Any ideas on what I'm missing?

Thanks