I'm trying to relay the Drop event to a command.  Why doesn't the following work...

<Border Background="#f7f7f7" BorderBrush="#ccc" BorderThickness="1" Margin="2" Padding="4" Cursor="SizeAll">

                                        <ig:DragDropManager.DragSource>

                                            <ig:DragSource IsDraggable="True">

                                                <i:Interaction.Triggers>

                                                    <i:EventTrigger EventName="Drop">

                                                        <i:InvokeCommandAction Command="{Binding DataContext.AddChartCommand, ElementName=ReportDocumentView}"/>

                                                    </i:EventTrigger>

                                                </i:Interaction.Triggers>

                                            </ig:DragSource>

                                        </ig:DragDropManager.DragSource>

                                        <TextBlock Text="{Binding DisplayName}"/>

                                    </Border>

Is it because DragSource uses a regular event instead of a routedevent?  Is that a requirement for EventTrigger?  Also, just fyi, I tested the InvokeCommand code on a button's click event and it worked fine.  It just doesn't work when attached to the DragSource.