EndSelect() cannot be used with SelectDisplay().
Please note that the SelectXXX()/
EndSelect() calls do not nest, i.e.
EndSelect() will always select the display as the output device, even
if it was not the output device when SelectXXX() was called.
SelectBrush(1) Box(0, 0, 100, 100, #RED) ; draw box on brush #1 SelectBrush(2) Box(0, 0, 100, 100, #GREEN) ; draw box on brush #2 EndSelect ; selects display (not brush #1 !!!) EndSelect ; Error! Display already selected!