New() resurrecting old disposed instances (crash)

Hi there

I'm having a problem that I'm not sure how to fix. When my android app starts, I create a new object, and when the app ends I Dispose() the object and set it to null. The next time I start, allocating a new object seems to always use the old disposed object and causes a crash.

Some example code (from the MainActivity.cs file):

private ShelterGame g = null;

protected override void OnResume ()
{
    if (g == null) {
        ShelterGame.Activity = this;
        g = new ShelterGame ();
        SetContentView (g.Window);
        g.Run ();
    }

    base.OnResume ();
}

protected override void OnDestroy ()
{
    base.OnDestroy ();
    g.Dispose ();
    g = null;
    GC.Collect (GC.MaxGeneration);
}

On every second run of the app, the variable g uses the same ShelterGame object from the previous run which has been disposed and is therefore invalid. I have added breakpoints and know that the correct code is hit at the correct intervals (and on the second run, new ShelterGame(); is definitely called.

Is there a way for me to prevent this and ensure that on every run of the app, the disposed object is fully collected and a genuinely new object is allocated and constructed?

On a side note, exiting my app (A MonoGame game) does not seem to detach the debugger. Is there something that could cause this that might be related?

Thanks

Chris