Strange Handle names.

I am working on an editor spline editor. ^^ I have a custom inspector and in the OnSceneGUI function I create free move handles (Handles.FreeMoveHandle(...)) for every control point of the spline. Before each handle, I make a call to GUI.SetNextControlName(SplineName + " CP" + ControlPointNumber) and after making all the handles, I ask the GUI which one has focus (GUI.GetNameOfFocusedControl()).

Now when I start comparing the name I get back from that GUI function, the strange thing is that the SplineName is often something random (like the name of a different Spline in the scene). The " CP" and ControlPointNumber are always right, but the name of the spline is often random (always a name of a spline that's in the scene though).

So, how is it possible that when I only make x handles in my OnSceneGUI with certain names, that I get a name back that isn't one of the x names that I gave for the handles?