Silverlight 4 ContextMenu and ScaleTransform

Question

The ContextMenu provided by the Silverlight 4 Toolkit worked great until I implemented a <RenderTransform> tag in my XAML in order to have the Silverlight app scale to fit the entire browser window (following this little tutorial)

When all worked great, before the tutorial, my XAML looked like:

<UserControl>
    <Grid>
        <!-- Rest of app here... -->
    </Grid>
</UserControl>

Now, my app looks like:

<UserControl>
    <Canvas>
        <Canvas.RenderTransform>
            <ScaleTransform [vars]></ScaleTransform>
        </Canvas.RenderTransform>
        <Grid>
            <!-- Rest of app here... -->
        </Grid>
    </Canvas>
</UserControl>

The scaling works perfectly, but now when I right click, the ContextMenu doesn't appear where it should (under the mouse). Instead, it appears at the same x-position as the mouse, but it shows up at the very top of the app. It's also very buggy, I have to keep clicking around to get it to go away, and I can't right click somewhere else to bring it up again, and it doesn't scale along with the rest of the app.

What might be causing this? Is there a correct way to go about fixing this, or should I just apply an offset to the menu to move it to the mouse?

Answer 1

You will need to pass the cursor coordinates through the inverse of your scale transformation to convert the screen point to a point your application understands.