face_cachels size limit?

Important property of any cache is limited capacity. If it grows too large, searches in it will take too much time and cache will slow down work rather than accelerating it. Does xemacs put any limit on size of `face_cachels' in `struct window'? <URL:info:internals> says: So it is nearly impossible to decide that particular performance test of redisplay shows that something is wrong. We have no estimates, how much resources should be used by current algorithm in which cases. We can not say: this (mis-) performance is inevitable unless we invent a considerably better algorithm; and this is apparently a bug / leak.