I've just noticed that ExtGraph's demo33, which tests DrawClipLine and the equivalent ExtGraph routine, when run under PedroM, corrupts the screen and the heap (and everything in-between), before crashing, which triggers a full reset (<= corrupted heap).
The lines in the top-left quarter of the screen are fine, the crashes happens when drawing the vertical line (or perhaps, the first line of the top-right quarter of the screen).