private void TranslatePosition(Gdk.Window current, double eventX, double eventY, out int x, out int y)
{
x = (int)eventX;
y = (int)eventY;
while (current != window.Window) {
int cx, cy, cw, ch;
current.GetGeometry (out cx, out cy, out cw, out ch);
x += cx;
y += cy;
current = current.Parent;
}
}