diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index adcb41b066..4a60167953 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -26,7 +26,7 @@ Code must be portable, memory-efficient, and bare-metal safe.
 ## Embedded Performance (flag in hot paths)
 
 - No heap allocation in draw loops, event handlers, timer callbacks
-- Avoid `lv_obj_belongs_to_display()` in internal callbacks — walks parent chain plus scans display screen lists
+- Avoid `lv_obj_is_in_widget_tree()` in internal callbacks — walks parent chain plus scans display screen lists
 - `lv_free(NULL)` is safe — no redundant NULL check before it
 
 ## Naming & Style
diff --git a/.github/instructions/c-code.instructions.md b/.github/instructions/c-code.instructions.md
index c88ac2932c..03a4e76c0a 100644
--- a/.github/instructions/c-code.instructions.md
+++ b/.github/instructions/c-code.instructions.md
@@ -24,7 +24,7 @@ applyTo: "src/**/*.c,src/**/*.h"
 
 - No heap allocation in hot paths (draw loops, event handlers, timer callbacks)
 - Prefer stack allocation for small temporary buffers
-- Avoid `lv_obj_belongs_to_display()` in internal callbacks — it walks up the parent chain and scans every display's screen list
+- Avoid `lv_obj_is_in_widget_tree()` in internal callbacks — it walks up the parent chain and scans every display's screen list
 - Cache-friendly access: sequential over random
 - Struct member ordering: pointers first, then int32_t, then smaller types/bitfields — minimizes padding
 
diff --git a/Kconfig b/Kconfig
index ca51a6bfe5..1ab96f9472 100644
--- a/Kconfig
+++ b/Kconfig
@@ -881,16 +881,16 @@ menu "LVGL configuration"
 				depends on LV_USE_CHECK_ARG
 				help
 					When enabled, LV_CHECK_OBJ also verifies that the object is
-					still part of the widget tree (lv_obj_belongs_to_display). When
+					still part of the widget tree (lv_obj_is_in_widget_tree). When
 					disabled, the validity check is skipped (only the class/NULL
 					check remains).
 
 			config LV_USE_CHECK_OBJ_PARENT_LINK
-				bool "Enable parent-link consistency check in lv_obj_belongs_to_display"
+				bool "Enable parent-link consistency check in lv_obj_is_in_widget_tree"
 				default n
 				depends on LV_USE_CHECK_OBJ_VALIDITY
 				help
-					When enabled, lv_obj_belongs_to_display verifies — while walking
+					When enabled, lv_obj_is_in_widget_tree verifies — while walking
 					up the parent chain — that each parent's children array actually
 					contains the child. This catches corruption where a child's
 					parent pointer disagrees with the parent's children list. Slower
diff --git a/include/lvgl/config/lv_conf_internal.h b/include/lvgl/config/lv_conf_internal.h
index 9f81902b81..1b077c6112 100644
--- a/include/lvgl/config/lv_conf_internal.h
+++ b/include/lvgl/config/lv_conf_internal.h
@@ -1582,7 +1582,7 @@
 #endif
 
 /** If enabled, LV_CHECK_OBJ will also verify that the object is still part of the
- * widget tree (lv_obj_belongs_to_display). When disabled the validity check is skipped
+ * widget tree (lv_obj_is_in_widget_tree). When disabled the validity check is skipped
  * (only the class/NULL check remains).
  * Requires LV_USE_CHECK_ARG to be enabled. */
 #ifndef LV_USE_CHECK_OBJ_VALIDITY
@@ -1593,7 +1593,7 @@
     #endif
 #endif
 
-/** If enabled, lv_obj_belongs_to_display will verify — while walking up the parent chain —
+/** If enabled, lv_obj_is_in_widget_tree will verify — while walking up the parent chain —
  * that each parent's children array actually contains the child.
  * This catches corruption where a child's parent pointer disagrees with the
  * parent's children list. Slower than the basic reachability check (O(siblings)
diff --git a/include/lvgl/core/lv_obj.h b/include/lvgl/core/lv_obj.h
index 56ccb376d5..020eaf728b 100644
--- a/include/lvgl/core/lv_obj.h
+++ b/include/lvgl/core/lv_obj.h
@@ -702,12 +702,12 @@ const lv_obj_class_t * lv_obj_get_class(const lv_obj_t * obj);
  * @param obj   pointer to an object
  * @return      true if the root of `obj`'s parent chain is a registered screen
  */
-bool lv_obj_belongs_to_display(const lv_obj_t * obj);
+bool lv_obj_is_in_widget_tree(const lv_obj_t * obj);
 
 /**
- * @deprecated Use `lv_obj_belongs_to_display` instead.
+ * @deprecated Use `lv_obj_is_in_widget_tree` instead.
  */
-LV_DEPRECATED("Use lv_obj_belongs_to_display instead")
+LV_DEPRECATED("Use lv_obj_is_in_widget_tree instead")
 bool lv_obj_is_valid(const lv_obj_t * obj);
 
 /**
@@ -880,7 +880,7 @@ void lv_objid_builtin_destroy(void);
         LV_DEPRECATED_MACRO_WARN("LV_ASSERT_OBJ is deprecated. Use LV_CHECK_OBJ instead.");             \
         LV_ASSERT_MSG(obj_p != NULL, "The object is NULL");                                             \
         LV_ASSERT_MSG(lv_obj_has_class(obj_p, obj_class) == true, "Incompatible object type.");         \
-        LV_ASSERT_MSG(lv_obj_belongs_to_display(obj_p)  == true, "The object is invalid, deleted or corrupted?"); \
+        LV_ASSERT_MSG(lv_obj_is_in_widget_tree(obj_p)  == true, "The object is invalid, deleted or corrupted?"); \
     } while(0)
 # else
 /**
diff --git a/include/lvgl/debugging/lv_check_obj.h b/include/lvgl/debugging/lv_check_obj.h
index 9e64a14c98..930fc177e9 100644
--- a/include/lvgl/debugging/lv_check_obj.h
+++ b/include/lvgl/debugging/lv_check_obj.h
@@ -63,7 +63,7 @@ extern "C" {
      */
     #define LV_CHECK_OBJ_VALID(obj, cls, action) \
       LV_CHECK_OBJ_CLASS(obj, cls, action); \
-      LV_CHECK_ARG(lv_obj_belongs_to_display(obj), action);
+      LV_CHECK_ARG(lv_obj_is_in_widget_tree(obj), action);
 #else
     #define LV_CHECK_OBJ_VALID(obj, cls, action) LV_CHECK_OBJ_CLASS(obj, cls, action);
 #endif
diff --git a/lv_conf_template.h b/lv_conf_template.h
index a850109a43..9efeb279a2 100644
--- a/lv_conf_template.h
+++ b/lv_conf_template.h
@@ -555,12 +555,12 @@
 #define LV_USE_CHECK_OBJ_CLASSTYPE 0
 
 /** If enabled, LV_CHECK_OBJ will also verify that the object is still part of the
- * widget tree (lv_obj_belongs_to_display). When disabled the validity check is skipped
+ * widget tree (lv_obj_is_in_widget_tree). When disabled the validity check is skipped
  * (only the class/NULL check remains).
  * Requires LV_USE_CHECK_ARG to be enabled. */
 #define LV_USE_CHECK_OBJ_VALIDITY 0
 
-/** If enabled, lv_obj_belongs_to_display will verify — while walking up the parent chain —
+/** If enabled, lv_obj_is_in_widget_tree will verify — while walking up the parent chain —
  * that each parent's children array actually contains the child.
  * This catches corruption where a child's parent pointer disagrees with the
  * parent's children list. Slower than the basic reachability check (O(siblings)
diff --git a/src/core/lv_obj.c b/src/core/lv_obj.c
index 8bf225ad65..a97897b519 100644
--- a/src/core/lv_obj.c
+++ b/src/core/lv_obj.c
@@ -1125,7 +1125,7 @@ const lv_obj_class_t * lv_obj_get_class(const lv_obj_t * obj)
     return obj->class_p;
 }
 
-bool lv_obj_belongs_to_display(const lv_obj_t * obj)
+bool lv_obj_is_in_widget_tree(const lv_obj_t * obj)
 {
     LV_CHECK_ARG(obj != NULL, return false);   /* Can't use LV_CHECK_OBJ here, it could cause an infinite recursion loop. */
 
@@ -1151,7 +1151,7 @@ bool lv_obj_belongs_to_display(const lv_obj_t * obj)
 
 bool lv_obj_is_valid(const lv_obj_t * obj)
 {
-    return lv_obj_belongs_to_display(obj);
+    return lv_obj_is_in_widget_tree(obj);
 }
 
 void lv_obj_null_on_delete(lv_obj_t ** obj_ptr)
diff --git a/src/core/lv_obj_tree.c b/src/core/lv_obj_tree.c
index 2ccb8d2037..13906263ec 100644
--- a/src/core/lv_obj_tree.c
+++ b/src/core/lv_obj_tree.c
@@ -738,7 +738,7 @@ static void obj_delete_core(lv_obj_t * obj)
     }
 
     /*Clear the parent pointer so that, if the freed memory happens to still be
-     *readable, lv_obj_belongs_to_display has a better chance of rejecting it
+     *readable, lv_obj_is_in_widget_tree has a better chance of rejecting it
      *(the chain will terminate at NULL and miss every display's screen list).
      *
      *WARNING: reading any field of a freed object is use-after-free and
diff --git a/src/widgets/ime/lv_ime_pinyin.c b/src/widgets/ime/lv_ime_pinyin.c
index 1f07ab5378..6534f9913a 100644
--- a/src/widgets/ime/lv_ime_pinyin.c
+++ b/src/widgets/ime/lv_ime_pinyin.c
@@ -597,11 +597,11 @@ static void lv_ime_pinyin_destructor(const lv_obj_class_t * class_p, lv_obj_t *
 
     lv_ime_pinyin_t * pinyin_ime = (lv_ime_pinyin_t *)obj;
 
-    if(pinyin_ime->kb != NULL)
-        lv_obj_delete(pinyin_ime->kb);
+    lv_obj_delete(pinyin_ime->kb);
+    pinyin_ime->kb = NULL;
 
-    if(pinyin_ime->cand_panel != NULL)
-        lv_obj_delete(pinyin_ime->cand_panel);
+    lv_obj_delete(pinyin_ime->cand_panel);
+    pinyin_ime->cand_panel = NULL;
 
 #if LV_IME_PINYIN_USE_K9_MODE
     lv_ll_clear(&pinyin_ime->k9_legal_py_ll);
diff --git a/tests/src/test_cases/test_screen_load.c b/tests/src/test_cases/test_screen_load.c
index 78e06360a6..401691e7dc 100644
--- a/tests/src/test_cases/test_screen_load.c
+++ b/tests/src/test_cases/test_screen_load.c
@@ -51,7 +51,7 @@ void test_screen_load_with_delete_no_crash(void)
     /*Check for the screens status after the transition*/
     TEST_ASSERT_NULL(screen_with_anim_1);
     TEST_ASSERT_NULL(screen_with_anim_2);
-    TEST_ASSERT_TRUE(lv_obj_belongs_to_display(screen_with_anim_3));
+    TEST_ASSERT_TRUE(lv_obj_is_in_widget_tree(screen_with_anim_3));
 }
 
 void test_screen_load_with_delete_no_crash2(void)
@@ -90,7 +90,7 @@ void test_screen_load_with_delete_no_crash2(void)
     TEST_ASSERT_NULL(screen_with_anim_1);
     TEST_ASSERT_NULL(screen_with_anim_2);
     TEST_ASSERT_NULL(screen_with_anim_3);
-    TEST_ASSERT_TRUE(lv_obj_belongs_to_display(screen_with_anim_4));
+    TEST_ASSERT_TRUE(lv_obj_is_in_widget_tree(screen_with_anim_4));
 }
 
 static bool screen_1_unloaded_called = false;
@@ -140,7 +140,7 @@ void test_screen_load_with_delete_event(void)
     TEST_ASSERT_NULL(screen_with_anim_1);
     TEST_ASSERT_NULL(screen_with_anim_2);
     TEST_ASSERT_NULL(screen_with_anim_3);
-    TEST_ASSERT_TRUE(lv_obj_belongs_to_display(screen_with_anim_4));
+    TEST_ASSERT_TRUE(lv_obj_is_in_widget_tree(screen_with_anim_4));
 }
 
 static size_t display_screen_load_start = 0;
diff --git a/tests/src/test_cases/widgets/test_ime_pinyin.c b/tests/src/test_cases/widgets/test_ime_pinyin.c
index c35259f6f2..3d162e6745 100644
--- a/tests/src/test_cases/widgets/test_ime_pinyin.c
+++ b/tests/src/test_cases/widgets/test_ime_pinyin.c
@@ -391,14 +391,14 @@ void test_ime_pinyin_kb_validity(void)
     lv_ime_pinyin_set_keyboard(g_pinyin_ime, g_kb);
 
     lv_obj_t * retrieved = lv_ime_pinyin_get_kb(g_pinyin_ime);
-    TEST_ASSERT_TRUE(lv_obj_belongs_to_display(retrieved));
+    TEST_ASSERT_TRUE(lv_obj_is_in_widget_tree(retrieved));
 }
 
 /* Test cand_panel object validity */
 void test_ime_pinyin_cand_panel_validity(void)
 {
     lv_obj_t * cand_panel = lv_ime_pinyin_get_cand_panel(g_pinyin_ime);
-    TEST_ASSERT_TRUE(lv_obj_belongs_to_display(cand_panel));
+    TEST_ASSERT_TRUE(lv_obj_is_in_widget_tree(cand_panel));
 }
 
 /* Test getter functions */
@@ -414,7 +414,7 @@ void test_ime_pinyin_getters(void)
     /* Test get_cand_panel */
     lv_obj_t * cand_panel = lv_ime_pinyin_get_cand_panel(g_pinyin_ime);
     TEST_ASSERT_NOT_NULL(cand_panel);
-    TEST_ASSERT_TRUE(lv_obj_belongs_to_display(cand_panel));
+    TEST_ASSERT_TRUE(lv_obj_is_in_widget_tree(cand_panel));
 
     /* Test get_dict (should return default dict) */
     const lv_pinyin_dict_t * dict = lv_ime_pinyin_get_dict(g_pinyin_ime);
@@ -431,7 +431,7 @@ void test_ime_pinyin_edge_cases(void)
 
     /* Verify cand_panel is valid */
     lv_obj_t * cand_panel = lv_ime_pinyin_get_cand_panel(g_pinyin_ime);
-    TEST_ASSERT_TRUE(lv_obj_belongs_to_display(cand_panel));
+    TEST_ASSERT_TRUE(lv_obj_is_in_widget_tree(cand_panel));
 }
 
 /* Test rendering with default dictionary */