void NextItem()
{
++focusIndex;
if (focusIndex >= toolItems.Count)
{
focusIndex = 0;
}
focusItem.UnfocusItem();
focusItem = toolItems[focusIndex];
ShiftItems();
focusItem.FocusItem();
if (activeHighlight)
{
LowlightAll();
focusItem.Highlight();
}
}