diff --git a/sdk/python/packages/flet-core/src/flet_core/clipboard.py b/sdk/python/packages/flet-core/src/flet_core/clipboard.py
index 31efa8bc5..9c346a2cb 100644
--- a/sdk/python/packages/flet-core/src/flet_core/clipboard.py
+++ b/sdk/python/packages/flet-core/src/flet_core/clipboard.py
@@ -26,7 +26,7 @@ def __init__(
     def _get_control_name(self):
         return "clipboard"
 
-    def _is_isolated(self):
+    def is_isolated(self):
         return True
 
     def set_data(self, data: str):
diff --git a/sdk/python/packages/flet-core/src/flet_core/control.py b/sdk/python/packages/flet-core/src/flet_core/control.py
index fd0ac18d4..f43f38f43 100644
--- a/sdk/python/packages/flet-core/src/flet_core/control.py
+++ b/sdk/python/packages/flet-core/src/flet_core/control.py
@@ -8,12 +8,6 @@
 from flet_core.ref import Ref
 from flet_core.types import ResponsiveNumber
 
-try:
-    from typing import Literal
-except ImportError:
-    from typing_extensions import Literal
-
-
 if TYPE_CHECKING:
     from .page import Page
 
@@ -54,10 +48,10 @@ def __init__(
         if ref:
             ref.current = self
 
-    def _is_isolated(self):
+    def is_isolated(self):
         return False
 
-    def _build(self):
+    def build(self):
         pass
 
     def before_update(self):
@@ -407,7 +401,7 @@ def build_update_commands(
                         commands,
                         added_controls,
                         removed_controls,
-                        isolated=ctrl._is_isolated(),
+                        isolated=ctrl.is_isolated(),
                     )
                     n += 1
             elif tag == "insert":
@@ -451,7 +445,18 @@ def _remove_control_recursively(self, index, control):
     def _build_add_commands(self, indent=0, index=None, added_controls=None):
         if index:
             self.page = index["page"]
-        self._build()
+        content = self.build()
+
+        # fix for UserControl
+        if content is not None:
+            if isinstance(content, Control) and hasattr(self, "controls"):
+                self.controls = [content]
+            elif (
+                isinstance(content, List)
+                and hasattr(self, "controls")
+                and all(isinstance(control, Control) for control in content)
+            ):
+                self.controls = content
 
         # remove control from index
         if self.__uid and index is not None and self.__uid in index:
diff --git a/sdk/python/packages/flet-core/src/flet_core/haptic_feedback.py b/sdk/python/packages/flet-core/src/flet_core/haptic_feedback.py
index 97ae90a22..f09fc3521 100644
--- a/sdk/python/packages/flet-core/src/flet_core/haptic_feedback.py
+++ b/sdk/python/packages/flet-core/src/flet_core/haptic_feedback.py
@@ -47,7 +47,7 @@ def __init__(
     def _get_control_name(self):
         return "hapticfeedback"
 
-    def _is_isolated(self):
+    def is_isolated(self):
         return True
 
     def heavy_impact(self):
diff --git a/sdk/python/packages/flet-core/src/flet_core/matplotlib_chart.py b/sdk/python/packages/flet-core/src/flet_core/matplotlib_chart.py
index cc3d078cb..ea307b0a8 100644
--- a/sdk/python/packages/flet-core/src/flet_core/matplotlib_chart.py
+++ b/sdk/python/packages/flet-core/src/flet_core/matplotlib_chart.py
@@ -126,10 +126,10 @@ def __init__(
         self.original_size = original_size
         self.transparent = transparent
 
-    def _is_isolated(self):
+    def is_isolated(self):
         return self.__isolated
 
-    def _build(self):
+    def build(self):
         self.alignment = alignment.center
         self.__img = Image(fit="fill")
         self.content = self.__img
diff --git a/sdk/python/packages/flet-core/src/flet_core/plotly_chart.py b/sdk/python/packages/flet-core/src/flet_core/plotly_chart.py
index 51270c081..387eb76e4 100644
--- a/sdk/python/packages/flet-core/src/flet_core/plotly_chart.py
+++ b/sdk/python/packages/flet-core/src/flet_core/plotly_chart.py
@@ -107,10 +107,10 @@ def __init__(
         self.isolated = isolated
         self.original_size = original_size
 
-    def _is_isolated(self):
+    def is_isolated(self):
         return self.__isolated
 
-    def _build(self):
+    def build(self):
         self.alignment = alignment.center
         self.__img = Image(fit="fill")
         self.content = self.__img
diff --git a/sdk/python/packages/flet-core/src/flet_core/user_control.py b/sdk/python/packages/flet-core/src/flet_core/user_control.py
index a89d8b402..87382174d 100644
--- a/sdk/python/packages/flet-core/src/flet_core/user_control.py
+++ b/sdk/python/packages/flet-core/src/flet_core/user_control.py
@@ -1,6 +1,3 @@
-from typing import List
-
-from flet_core.control import Control
 from flet_core.stack import Stack
 
 
@@ -8,18 +5,5 @@ class UserControl(Stack):
     def build(self):
         pass
 
-    def _build(self):
-        content = self.build()
-        if isinstance(content, Control):
-            self.controls = [content]
-        elif isinstance(content, List) and all(
-            isinstance(control, Control) for control in content
-        ):
-            self.controls = content
-        else:
-            raise Exception(
-                f"{self.__class__.__name__}.build() method must be implemented and returning either Control or List[Control]."
-            )
-
-    def _is_isolated(self):
+    def is_isolated(self):
         return True