Virtual object - highlight & selection

Hello community.

I use AIS framework to display some 3D data and I create measure objects, such as distance and angles, and display them creating a root object and child objects (lines / arcs / labels).

To do so, the root object I used is actually an AIS_Trihedron with its axes / arrows and labels hidden:

Handle(Prs3d_DatumAspect) trihedronAspect = new Prs3d_DatumAspect();
trihedronAspect->SetDrawLabels(Standard_False);
trihedronAspect->SetDrawArrows(Standard_False);
trihedronAspect->LineAspect(Prs3d_DatumParts::Prs3d_DP_XAxis)->SetTypeOfLine(Aspect_TypeOfLine::Aspect_TOL_EMPTY);
trihedronAspect->LineAspect(Prs3d_DatumParts::Prs3d_DP_YAxis)->SetTypeOfLine(Aspect_TypeOfLine::Aspect_TOL_EMPTY);
trihedronAspect->LineAspect(Prs3d_DatumParts::Prs3d_DP_ZAxis)->SetTypeOfLine(Aspect_TypeOfLine::Aspect_TOL_EMPTY);

Then, I add child objects to the trihedron (lines / labels ...).
First attachment shows an example of a measure line displayed in my 3D viewer.

First, I was surprised that I couldn't find any virtual object that may only hold children and draw nothing special but it doesn't matter using a trihedron to hold all needed objects.

My main problem is that I need to highlight and select this full object, not only selecting one line or the label but the entire object, pointing the cursor on any line or label and I can't achieve this.

To display the trihedron, I use this code:

trihedron->SetContext(myInteractiveContext);
myInteractiveContext->Display(trihedron, 0, AIS_TrihedronSelectionMode_EntireObject, Standard_False);
myInteractiveContext->SetZLayer(trihedron, this->zLayerMeasureObjectsId);
trihedron->SetDynamicHilightAttributes(myInteractiveContext->HighlightStyle(Prs3d_TypeOfHighlight_Dynamic));
trihedron->SetHilightAttributes(myInteractiveContext->HighlightStyle(Prs3d_TypeOfHighlight_Selected));

To display a line / label / arc, I use this code (example for a line):

line->SetContext(myInteractiveContext);
myInteractiveContext->Display(line, 0, -1, Standard_False);
myInteractiveContext->SetZLayer(line, this->zLayerMeasureObjectsId);
line->SetDynamicHilightAttributes(myInteractiveContext->HighlightStyle(Prs3d_TypeOfHighlight_Dynamic));
line->SetHilightAttributes(myInteractiveContext->HighlightStyle(Prs3d_TypeOfHighlight_Selected));

I can select the complete object, but it appears that it's not when the mouse cursor is under any of these lines as you can see in second attachment. I suppose it happens when the cursor is in fact under any axis of the trihedron while these axes are not displayed.

I really don't know how to achieve my goal. If someone can give my a good hint it would really help me.

Thank you very much.