if (fgStructure.CurrentWindow->Parent && (eWhat==GLUT_WINDOW_X || eWhat==GLUT_WINDOW_Y))
{
/* For child window, we should return relative to upper-left
if (fgStructure.CurrentWindow->Parent && (eWhat==GLUT_WINDOW_X || eWhat==GLUT_WINDOW_Y))
{
/* For child window, we should return relative to upper-left