What you are describing is indicating that there is still an existing object reference to the object you think you have released. This reference will keep it alive until its cut. This is why it disappears when you call CLEAR ALL. Have a look in the "locals" window of the debugger and watch out for existing objects.

nox=create("form")
nox.AddObject("label","label")
nox.Show

alive=nox.label &&create an additional reference
nox.Release && nox released but form still visible
release nox && form is still there
nox.release && object nox does not exist any more

RELEASE alive && gone