{
	/* Manfred Steinbach 03-oct-2018
	Problem with property ->referencedEntity() of <SketchCurves>
		- works fine when projections were done with edge-entities
		- problem when projection were done with faces => "InternalValidationError : res" 

	example-files (*f3d) 
		- "example referencedEntity problem-projection of edges-ok"
		- "example referencedEntity problem-projection of faces-problem"

		=> to test please select sketch: "Sketch with projections" in component: "plate" 
	*/

	app = Application::get();
	if (!app) return false;
	ui = app->userInterface();
	if (!ui) return false;

	// select sketch by user
	Ptr<Selection> uiSelSketch = ui->selectEntity("select sketch", "Sketches");
	if (!uiSelSketch) return false;
	Ptr<Sketch> sketch = uiSelSketch->entity();								// selected sketch
	if (!sketch) return false;

	// analyze sketch-curves (necessary for further operations)
	Ptr<SketchCurves> skCurves = sketch->sketchCurves();
	
	for (int i = 0; i < skCurves->count(); ++i) {				// traverse sketch-curves
		Ptr<SketchCurve> skCurve = skCurves->item(i);
		if (skCurve->isReference()) {							// is sketch-curve a reference (projected geometry)?
			Ptr<Base> base = skCurve->referencedEntity();		// referenced geometry (source)
			if (!base)
			{
				std::string errorMessage;
				int errorCode = app->getLastError(&errorMessage);
				if (GenericErrors::Ok != errorCode)
					ui->messageBox(errorMessage);
				return false;
			}
		}
	}
	ui->messageBox("done, no problems");

	return true;
}