initial layout setup and config learning

src/layout/horizontal.h

@@ -782,6 +782,17 @@ void right_tile(Monitor *m) {
 	}
 }
 
+void dual_scroller(Monitor *m) {
+	Client *c = NULL;
+	wl_list_for_each(c, &clients, link) {
+		c->geom.x = m->w.x;
+		c->geom.y = m->w.y;
+		c->geom.width = m->w.width;
+		c->geom.height = m->w.height;
+		resize(c, c->geom, 0);
+	}
+}
+
 void // 17
 monocle(Monitor *m) {
 	Client *c = NULL;
@@ -804,4 +815,4 @@ monocle(Monitor *m) {
 	}
 	if ((c = focustop(m)))
 		wlr_scene_node_raise_to_top(&c->scene->node);
-}
+}