Bad as in hard to read, update, and maintain. It certainly achieves useful results! Congratulations on managing such a large change. BTW, I just double-checked

Bad as in hard to read, update, and maintain. It certainly achieves useful results! Congratulations on managing such a large change. BTW, I just double-checked, and I can indeed make it flicker when resizing the window as you mention in emacs-devel. I guess I've just never noticed since I never resize anything (maximized windows or nothing).