diff --git a/src/event.c b/src/event.c
index 065e75b76e..be9df40a48 100644
--- a/src/event.c
+++ b/src/event.c
@@ -352,7 +352,6 @@ static inline void ev_create_notify(session_t *ps, xcb_create_notify_event_t *ev
 /// Handle configure event of a regular window
 static void configure_win(session_t *ps, xcb_configure_notify_event_t *ce) {
 	auto cursor = wm_find(ps->wm, ce->window);
-	auto below = wm_find(ps->wm, ce->above_sibling);
 
 	if (!cursor) {
 		if (wm_is_consistent(ps->wm)) {
@@ -363,17 +362,7 @@ static void configure_win(session_t *ps, xcb_configure_notify_event_t *ce) {
 		return;
 	}
 
-	if (below == NULL && ce->above_sibling != XCB_NONE) {
-		log_error("Configure event received for window %#010x, but its sibling "
-		          "window %#010x is not in our tree. Expect malfunction.",
-		          ce->window, ce->above_sibling);
-		assert(false);
-	} else if (below != NULL) {
-		wm_stack_move_to_above(ps->wm, cursor, below);
-	} else {
-		// above_sibling being XCB_NONE means the window is put at the bottom.
-		wm_stack_move_to_end(ps->wm, cursor, true);
-	}
+	wm_stack_move_to_above(ps->wm, cursor, ce->above_sibling);
 
 	auto w = wm_ref_deref(cursor);
 	if (!w) {
diff --git a/src/wm/wm.c b/src/wm/wm.c
index f0b3536044..2b3eecad56 100644
--- a/src/wm/wm.c
+++ b/src/wm/wm.c
@@ -266,16 +266,32 @@ void wm_refresh_leaders(struct wm *wm) {
 	}
 }
 
-/// Move window `w` so it's right above `below`, if `below` is 0, `w` is moved
+/// Move window `w` so it's right above `below`, if `below` is XCB_NONE, `w` is moved
 /// to the bottom of the stack
-void wm_stack_move_to_above(struct wm *wm, struct wm_ref *cursor, struct wm_ref *below) {
+void wm_stack_move_to_above(struct wm *wm, struct wm_ref *cursor, xcb_window_t below) {
+	BUG_ON_NULL(cursor);
 	auto node = to_tree_node_mut(cursor);
 	if (node->parent == &wm->orphan_root) {
 		// If this window is orphaned, moving it around its siblings is
 		// meaningless. Same below.
+		log_debug("Ignoring restack request for orphaned window %#010x", node->id.x);
 		return;
 	}
-	wm_tree_move_to_above(&wm->tree, node, to_tree_node_mut(below));
+	if (below == XCB_NONE) {
+		// `below` being XCB_NONE means the window is put at the bottom.
+		wm_tree_move_to_end(&wm->tree, node, /*to_bottom=*/true);
+		return;
+	}
+
+	auto below_node = wm_tree_find(&wm->tree, below);
+	if (below_node == NULL) {
+		log_error("Trying to restack window %#010x, but its sibling window "
+		          "%#010x is not in our tree. Expect malfunction.",
+		          node->id.x, below);
+		assert(false);
+		return;
+	}
+	wm_tree_move_to_above(&wm->tree, node, below_node);
 }
 
 void wm_stack_move_to_end(struct wm *wm, struct wm_ref *cursor, bool to_bottom) {
diff --git a/src/wm/wm.h b/src/wm/wm.h
index 7bb0facc32..421cd7a7b9 100644
--- a/src/wm/wm.h
+++ b/src/wm/wm.h
@@ -137,7 +137,7 @@ struct wm_ref *attr_pure wm_ref_bottommost_child(const struct wm_ref *cursor);
 
 /// Move window `w` so it's right above `below`, if `below` is 0, `w` is moved
 /// to the bottom of the stack
-void wm_stack_move_to_above(struct wm *wm, struct wm_ref *cursor, struct wm_ref *below);
+void wm_stack_move_to_above(struct wm *wm, struct wm_ref *cursor, xcb_window_t below);
 /// Move window `w` to the top of the stack.
 void wm_stack_move_to_end(struct wm *wm, struct wm_ref *cursor, bool to_bottom);