Never one of the room's objects: SHOW_CARRIED draws the carried things through it, and DISPLAY_PANEL and PRINT_BORDER the panel's frame and the border. They set its graphic (+0), its flags (+7) and its pixel position (+$1A, +$1B), and the sprite drawing (the entry into CALC_PIXEL_XY_AND_RENDER past the projection) writes +$18 and +$19. Zero on the tape.