I see what is happening. I hit CLEAN, the window pops up. I do not see the D0 in the window. But if I hit REFRESH button at the lower right, it clears the D0
I was pressing the CLEAN and when the window popped up, closed it and press the REFRESH icon next to clear. I closed the window cause D0 in not in the window to select!
I think this is misleading on the sequence on clearing unused elements. Since there is an ADD icon, why no DELETE icon. How is one suppose to know to press the REFRESH icon in the pop up window when the element you are trying to clear is not even in the window.
too much to type, hope you get my meaning.