BASE_SCREEN::~BASE_SCREEN(void)
/******************************/
{
	if ( m_ZoomList ) free(m_ZoomList);
	if ( m_GridList ) free(m_GridList);
	ClearUndoRedoList();
}
SCH_SCREEN::~SCH_SCREEN()
{
    ClearUndoRedoList();
    FreeDrawList();
}
PCB_SCREEN::~PCB_SCREEN()
{
    ClearUndoRedoList();
}
GBR_SCREEN::~GBR_SCREEN()
{
    ClearUndoRedoList();
}
PL_EDITOR_SCREEN::~PL_EDITOR_SCREEN()
{
    ClearUndoRedoList();
}