Memory not released after Remove function.

Hello,
I wish to express my gratitude for OpenCASCADE developers.

I have a question about OpenCASCADE 6.3 usage.
I used OpenCASCADE as follows.

(1) Set AutoActivateSelection OFF.
myAISContext->SetAutoActivateSelection(Standard_False);

(2) Create 3D object.
gp_Pnt point(0.0, 0.0, 0.0);
gp_Dir direction(1.0, 0.0, 0.0);
TopoDS_Shape cone = BRepPrimAPI_MakeCone(gp_Ax2(point, direction), 50.0, 0.0, 50.0);
Handle(AIS_Shape) handle = new AIS_Shape(cone);

(3) Display 3D object with DisplayMode index 1.
myAISContext->SetDisplayMode(handle, 1, Standard_False);
myAISContext->Display(handle, Standard_True);

(4) Delete 3D object.
myAISContext->Remove(handle);

After (4), memory seems to be not released.
I repeated steps (2)-(4) many times, then memory usage was increasing and
finally, memory was insufficient.
Is a wrong usage done?

---------------------------------------------------------
//Test code.
---------------------------------------------------------
void test() {
myAISContext->SetAutoActivateSelection(Standard_False);

for (int j = 0; j gp_Pnt point(0.0, 0.0, 0.0);
gp_Dir direction(1.0, 0.0, 0.0);
TopoDS_Shape cone = BRepPrimAPI_MakeCone(gp_Ax2(point, direction), 50.0, 0.0, 50.0);
Handle(AIS_Shape) handle = new AIS_Shape(cone);

myAISContext->SetDisplayMode(handle, 1, Standard_False);
myAISContext->Display(handle, Standard_True);

myAISContext->Remove(handle);
}
}
---------------------------------------------------------

* If displayed with DisplayMode index 0, memory usage was not increasing.
myAISContext->SetDisplayMode(handle, 0, Standard_False);

* If set AutoActivateSelection ON, memory usage was increasing.
myAISContext->SetAutoActivateSelection(Standard_True);

(My Environment)
- OpenCASCADE 6.3
- Windows XP (SP2) / Visual Studio 2005
(Using Visual C++ 6.0, the same problem happened.)

Yokoyama