GUI.SelectionGrid always Zero

I'm using the Popup.cs script found here.

This code:

    if (showList)
    {
        Rect listRect = new Rect(position.x, position.y+25, position.width, listStyle.CalcHeight(listContent[0], 1.0f) * listContent.Length);
        GUI.Box(listRect, "", boxStyle);
        listEntry = GUI.SelectionGrid(listRect, listEntry, listContent, 1, listStyle);
        Debug.Log("listEntry " + listEntry.ToString());
    }

is always showing 0, regardless of which element I mouseup on. Any ideas on what may be happening? My listEntry value is a global, so it is not being reset to 0 each OnGUI call.

I am having the same problem. It seems to occur when adding the 25 to the y position of the Rect:

position.y+25

Did you sort it out?