LayoutItem
BLayoutItem* LayoutItem() const;
GroupLayout()->AddItem(index, tab->LayoutItem());
return GroupLayout()->IndexOfItem(tab->LayoutItem());
index = GroupLayout()->IndexOfItem(tab->LayoutItem());
if (!tab->LayoutItem()->IsVisible())
LayoutItem()->InvalidateLayout();
BLayoutItem* LayoutItem() const;
if (LayoutItem())
layout->AddItem(LayoutItem(), left, top, right, bottom);