diff --git a/src/event.c b/src/event.c
index 7cd50a2..87de238 100644
--- a/src/event.c
+++ b/src/event.c
@@ -263,21 +263,8 @@ static inline void ev_configure_notify(session_t *ps, xcb_configure_notify_event
 
 static inline void ev_destroy_notify(session_t *ps, xcb_destroy_notify_event_t *ev) {
 	auto w = find_win(ps, ev->window);
-	auto mw = find_toplevel(ps, ev->window);
-	if (mw && mw->client_win == mw->base.id) {
-		// We only want _real_ frame window
-		assert(&mw->base == w);
-		mw = NULL;
-	}
-	assert(w == NULL || mw == NULL);
-
-	if (w != NULL) {
+	if (w) {
 		auto _ attr_unused = destroy_win_start(ps, w);
-	} else if (mw != NULL) {
-		win_recheck_client(ps, mw);
-	} else {
-		log_debug("Received a destroy notify from an unknown window, %#010x",
-		          ev->window);
 	}
 }
 
@@ -349,13 +336,15 @@ static inline void ev_reparent_notify(session_t *ps, xcb_reparent_notify_event_t
 		    ps->c, ev->window, XCB_CW_EVENT_MASK,
 		    (const uint32_t[]){determine_evmask(ps, ev->window, WIN_EVMODE_UNKNOWN)});
 
-		// Mark the window as the client window of its parent.
-		auto w_real_top = find_managed_window_or_parent(ps, ev->parent);
-		// If found, and the client window has not been determined, or its
-		// frame may not have a correct client, continue
-		if (w_real_top) {
-			if (!w_real_top->client_win ||
-			    w_real_top->client_win == w_real_top->base.id) {
+		// Check if the window is an undetected client window
+		// Firstly, check if it's a known client window
+		if (!w_top) {
+			// If not, look for its frame window
+			auto w_real_top = find_managed_window_or_parent(ps, ev->parent);
+			// If found, and the client window has not been determined, or its
+			// frame may not have a correct client, continue
+			if (w_real_top && (!w_real_top->client_win ||
+			                   w_real_top->client_win == w_real_top->base.id)) {
 				// If it has WM_STATE, mark it the client window
 				if (wid_has_prop(ps, ev->window, ps->atoms->aWM_STATE)) {
 					w_real_top->wmwin = false;
@@ -370,11 +359,6 @@ static inline void ev_reparent_notify(session_t *ps, xcb_reparent_notify_event_t
 					        determine_evmask(ps, ev->window, WIN_EVMODE_UNKNOWN) |
 					        XCB_EVENT_MASK_PROPERTY_CHANGE});
 				}
-			} else {
-				log_warn("Window %#010x reparented to a window that "
-				         "already has a client window, the parent is "
-				         "%#010x (%s)",
-				         ev->window, w_real_top->base.id, w_real_top->name);
 			}
 		}
 	}
diff --git a/src/picom.c b/src/picom.c
index d159dff..a7bc763 100644
--- a/src/picom.c
+++ b/src/picom.c
@@ -303,9 +303,9 @@ uint32_t determine_evmask(session_t *ps, xcb_window_t wid, win_evmode_t mode) {
 	struct managed_win *w = NULL;
 
 	// Check if it's a mapped frame window
-	if (mode == WIN_EVMODE_FRAME ||
+	if (WIN_EVMODE_FRAME == mode ||
 	    ((w = find_managed_win(ps, wid)) && w->a.map_state == XCB_MAP_STATE_VIEWABLE)) {
-		evmask |= XCB_EVENT_MASK_PROPERTY_CHANGE | XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY;
+		evmask |= XCB_EVENT_MASK_PROPERTY_CHANGE;
 		if (!ps->o.use_ewmh_active_win) {
 			evmask |= XCB_EVENT_MASK_FOCUS_CHANGE;
 		}
diff --git a/src/win.c b/src/win.c
index a9aa8ab..2da27eb 100644
--- a/src/win.c
+++ b/src/win.c
@@ -1037,8 +1037,6 @@ void win_mark_client(session_t *ps, struct managed_win *w, xcb_window_t client)
  */
 void win_unmark_client(session_t *ps, struct managed_win *w) {
 	xcb_window_t client = w->client_win;
-	log_debug("Detaching client window %#010x from frame %#010x (%s)", client,
-	          w->base.id, w->name);
 
 	w->client_win = XCB_NONE;
 
@@ -1054,7 +1052,7 @@ void win_unmark_client(session_t *ps, struct managed_win *w) {
  * @param ps current session
  * @param w struct _win of the parent window
  */
-void win_recheck_client(session_t *ps, struct managed_win *w) {
+static void win_recheck_client(session_t *ps, struct managed_win *w) {
 	// Initialize wmwin to false
 	w->wmwin = false;
 
@@ -1064,14 +1062,14 @@ void win_recheck_client(session_t *ps, struct managed_win *w) {
 	// sets override-redirect flags on all frame windows.
 	xcb_window_t cw = find_client_win(ps, w->base.id);
 	if (cw) {
-		log_debug("(%#010x): client %#010x", w->base.id, cw);
+		log_trace("(%#010x): client %#010x", w->base.id, cw);
 	}
 	// Set a window's client window to itself if we couldn't find a
 	// client window
 	if (!cw) {
 		cw = w->base.id;
 		w->wmwin = !w->a.override_redirect;
-		log_debug("(%#010x): client self (%s)", w->base.id,
+		log_trace("(%#010x): client self (%s)", w->base.id,
 		          (w->wmwin ? "wmwin" : "override-redirected"));
 	}
 
diff --git a/src/win.h b/src/win.h
index 738529c..d3d9071 100644
--- a/src/win.h
+++ b/src/win.h
@@ -299,7 +299,6 @@ void win_on_win_size_change(session_t *ps, struct managed_win *w);
 void win_update_wintype(session_t *ps, struct managed_win *w);
 void win_mark_client(session_t *ps, struct managed_win *w, xcb_window_t client);
 void win_unmark_client(session_t *ps, struct managed_win *w);
-void win_recheck_client(session_t *ps, struct managed_win *w);
 bool win_get_class(session_t *ps, struct managed_win *w);
 
 /**