Why my UserControl using a Path as ControlTemplate is not properly clickable? - wpf

Question

I created a class derived from UserControl, directly on code (without XAML), and defined a ControlTemplate in a ResourceDictionary. This control template is a pair of ellipses, as follows:
<ControlTemplate x:Key="MusclePositionControlTemplate" TargetType="{x:Type local:MusclePositionControl}">
<ControlTemplate.Resources>
<EllipseGeometry x:Key="bolinha" RadiusX="{StaticResource radius}" RadiusY="{StaticResource radius}">
<EllipseGeometry.Center>
<Point X="0" Y="{StaticResource distance}"/>
</EllipseGeometry.Center>
</EllipseGeometry>
</ControlTemplate.Resources>
<Path Fill="#9900ffff" StrokeThickness="1" Stroke="Black">
<Path.Data>
<GeometryGroup>
<StaticResource ResourceKey="bolinha"/>
<GeometryGroup>
<GeometryGroup.Transform>
<ScaleTransform ScaleY="-1"/>
</GeometryGroup.Transform>
<StaticResource ResourceKey="bolinha"/>
</GeometryGroup>
</GeometryGroup>
</Path.Data>
<Path.RenderTransform>
<TransformGroup>
<RotateTransform Angle="{Binding Angle, RelativeSource={RelativeSource Mode=TemplatedParent}}"/>
<TranslateTransform
X="{Binding X, RelativeSource={RelativeSource Mode=TemplatedParent}}"
Y="{Binding Y, RelativeSource={RelativeSource Mode=TemplatedParent}}"/>
</TransformGroup>
</Path.RenderTransform>
</Path>
</ControlTemplate>
When I edit this template in Blend, I can select the path clicking on it, and it displays its outlines like this:
But when I add the actual control to a canvas, with its X, Y and Angle properties set to some value, the control renders itself fine, but its defining geometry keeps being that of a rectangle at the origin, and this affects hit testing (I cannot select at design time, or click at runtime, by clicking at the shape itself):
So my questions are:
How should I create a ControlTemplate using a Path as "root" visual element, so that the clickable area of the control is that Path?
Assuming a Path should not or could not be used as root visual for a ControlTemplate, how should I achieve the same end result?