diff --git a/move_resize.c b/move_resize.c
index 84f5b24..4f6dac6 100644
--- a/move_resize.c
+++ b/move_resize.c
@@ -41,6 +41,8 @@ void jbwm_move_resize(struct JBWMClient * restrict c)
 	} // Skip shaped and fullscreen clients.
 	struct JBWMRectangle * restrict s = &c->size;
 	do_move(c->display, c->parent, c->window, s, offset);
+	/* Use the XOR of the dimension to track changes, thus avoiding
+	 * excessive updates. */
 	uint16_t szsum = s->width ^ s->height;
 	if (szsum != c->szsum) {
 		c->szsum = szsum;