While porting a Silverlight 2 Beta 2 app to RC0, I suddenly found my newly converted app would just terminate shortly after load. No exception messages, no JIT debugging, just death. The end result is that a blank area is left where the Silverlight application is supposed to be rendered. After setting breakpoints all over the place, I found that the Application_Exit event was being hit, but the Application_UnhandledException event was never being fired.

If this happens to you, I would recommend checking your Style definitions. In my case, I had a ListBoxItem style defined in my App.xaml, with a Foreground property. This property was fine in SL B2, but causes the nasty crash in SL RC0:

       <Style x:Key="ListBoxItemStyle1" TargetType="ListBoxItem">

            <Setter Property="Foreground" Value="#FF000000" />

            <Setter Property="Template">

                <Setter.Value>

                    <ControlTemplate TargetType="ListBoxItem">

                        <Grid x:Name="Root">

                            <ItemsPresenter  />

                            <ContentPresenter

                        Content="{TemplateBinding Content}"

                        Foreground="{TemplateBinding Foreground}" />

                        </Grid>

                    </ControlTemplate>

                </Setter.Value>

            </Setter>

        </Style>