void TreeCtrl::Open(int id, bool open)
{
	Item& m = item[id];
	if(m.isopen != open && (m.canopen || m.child.GetCount() || !open)) {
		m.isopen = open;
		int q = GetCursor();
		while(q >= 0) {
			q = GetParent(q);
			if(q == id) {
				SetCursor(id, true, true, true);
				break;
			}
		}
		Dirty(id);
		if(open)
			WhenOpen(id);
		else
			WhenClose(id);
	}
}

if(m.canopen || m.child.GetCount()) {
	Image im = m.isopen ? CtrlImg::treeminus() : CtrlImg::treeplus();
	op -= im.GetSize() / 2;
	w.DrawImage(op.x, op.y, im);