Created Issue: Toolkit v4 on WP7: ContextMenu appears outside screen [10022]

ContextMenu appears outside screen when triggered by a click at the bottom of the screen.

Bug reproducing steps are simple:
1. Create new WP7.1 app
2. Add this code to the MainPage.xaml

<!--ContentPanel - place additional content here-->
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<Grid Name="Grid" Background="Red">
<toolkit:ContextMenuService.ContextMenu>
<toolkit:ContextMenu x:Name="ContextMenu" IsZoomEnabled="False">
<toolkit:MenuItem Header="Menu item 1"/>
<toolkit:MenuItem Header="Menu item 2"/>
<toolkit:MenuItem Header="Menu item 3"/>
</toolkit:ContextMenu>
</toolkit:ContextMenuService.ContextMenu>
</Grid>
</Grid>

2. Run app and try to invoke context menu by clicking at the bottom of the screen

Screenshot:
https://skydrive.live.com/redir.aspx?cid=2884db12c13017c2&resid=2884DB12C13017C2!134&parid=root