Gong drag and drop: drag effect border does not fit element - wpf

Question

Using the gong drag and drop framework, one gets a drag effect, which is a simple border around the possible droptarget.
However, in my case for some reason this border doesn't fit the actual element, as shown here:
I have already tried to change background colors of the different xaml elements of the drop target to find out if some elements are bigger (but hidden), but couldn't find any.
I guess the problem is due to the usage of viewboxes, which I use, since the size of these drop targets is dynamic and zoom-able.
Here is the xaml code of drop target:
<Border BorderThickness="{Binding PlatformBorderThickness}" dd:DragDrop.IsDropTarget="True" dd:DragDrop.DropHandler="{StaticResource CustomDropHandler}" >
<Border.BorderBrush>
<LinearGradientBrush StartPoint="0,0" EndPoint="1,0" >
<GradientStop Color="Black" Offset="0"/>
<GradientStop Color="Black" Offset="0.1"/>
<GradientStop Color="Transparent" Offset="0.1"/>
<GradientStop Color="Transparent" Offset="0.9"/>
<GradientStop Color="Black" Offset="0.9"/>
<GradientStop Color="Black" Offset="1"/>
</LinearGradientBrush>
</Border.BorderBrush>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="10*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="10*"/>
</Grid.RowDefinitions>
<Viewbox Grid.Column="0" Grid.ColumnSpan="1" Grid.Row="0" Grid.RowSpan="1" HorizontalAlignment="Left">
<TextBlock Text="{Binding Equipment.Name, FallbackValue='Please add a device!'}" FontWeight="Bold"/>
</Viewbox>
<Viewbox Grid.Column="1" Grid.ColumnSpan="1" Grid.Row="0" Grid.RowSpan="1" Stretch="Uniform" HorizontalAlignment="Right">
<Button Command="{Binding DeleteButtonClick}" Background="Transparent" BorderThickness="0"
Margin="0" Padding="0">
<Image Source="/Resources/Cancel.ico"/>
</Button>
</Viewbox>
<Viewbox Grid.Column="0" Grid.ColumnSpan="3" Grid.Row="1" Grid.RowSpan="1" HorizontalAlignment="Left" VerticalAlignment="Top" Stretch="Uniform" Margin="2">
<DataGrid Width="200" Height="135" HeadersVisibility="None" RowBackground="Transparent" BorderThickness="0"
ItemsSource="{Binding Equipment.Settings}" SelectionMode="Single" AutoGenerateColumns="False" GridLinesVisibility="Vertical" CanUserAddRows="False"
GotFocus="DataGrid_GotFocus" Name="DutInfoGrid" >
<DataGrid.Resources>
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="Transparent"/>
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightTextBrushKey}" Color="Black"/>
<SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="Transparent"/>
</DataGrid.Resources>
<DataGrid.Background>
<ImageBrush ImageSource="{Binding Equipment.ImagePath, FallbackValue={StaticResource AddItemImage}, TargetNullValue={StaticResource AddItemImage}}"
Stretch="Fill" Opacity="0.25"/>
</DataGrid.Background>
<DataGrid.Columns>
<DataGridTemplateColumn >
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Button Name="DutInfoGridRemoveButton" Background="Transparent" BorderThickness="0" Margin="0" Padding="0" Height="15"
Command="{Binding Path=DataContext.RemoveClick, RelativeSource= {RelativeSource FindAncestor, AncestorType={x:Type DataGrid}}}"
CommandParameter="{Binding}">
<Image Source="/Resources/Trash.ico"/>
</Button>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTextColumn Binding="{Binding Items[3].Value}"/>
<DataGridTextColumn Binding="{Binding Items[6].Value}" />
</DataGrid.Columns>
</DataGrid>
</Viewbox>
</Grid>
</Border>
Edit:
After some further testing I found out that if I remove the ViewBox element around the datagrid, the problem is gone. Any ideas, why the ViewBox causes this issue and how to solve it?

Answer 1

You should probably switch to the action file, then swap and use jQuery with the XML code which will refer to the drag and drop.