diff --git a/conductor/code_styleguides/python.md b/conductor/code_styleguides/python.md
index 8376e4c..6de7fe2 100644
--- a/conductor/code_styleguides/python.md
+++ b/conductor/code_styleguides/python.md
@@ -16,8 +16,9 @@ is processed by AI agents, while preserving readability for human review.
 
 - **Hard limit: 5 levels maximum.**
 - AI agents consistently misinterpret Python scope via indentation. This hard limit prevents deeply nested blocks that confuse model interpretation.
-- **Enforcement:** Use ruff `max-c复-depth = 5` or flake8 `max-c复-depth = 5` in the project linter config.
-- **Refactoring mandate:** Any block exceeding 3 levels must be extracted into a named function. Do not "work around" this with tricks—extract the logic.
+- Classes and async handlers typically consume 1-2 levels before business logic begins, so 5 accommodates real-world usage patterns.
+- **Enforcement:** Use ruff `[tool.ruff.lint.mccabe] max-complexity = 5` in the project linter config.
+- **Refactoring mandate:** Any block exceeding 5 levels must be extracted into a named function. Do not "work around" this with tricks—extract the logic.
 - **Rationale:** GUI callbacks and async handlers naturally want to nest. This constraint forces extraction of deep logic into testable, named units.
 
 ## 2. Type Annotations
diff --git a/pyproject.toml b/pyproject.toml
index b0e4739..3ead2f4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -52,19 +52,21 @@ exclude = [
 ]
 
 [tool.ruff.lint]
+# Enable McCabe complexity check for nesting depth enforcement
+select = ["E", "F", "W", "C90", "C4"]
 
-# Enable standard rules
-select = ["E", "F", "W"]
 # Ignore style choices that conflict with project's compact style
 ignore = [
     "E701", # Multiple statements on one line (colon)
     "E702", # Multiple statements on one line (semicolon)
     "E402", # Module level import not at top of file
-    "E722", # Do not use bare `except`
     "E501", # Line too long
     "W291", # Trailing whitespace
     "W293", # Blank line contains whitespace
 ]
 
+[tool.ruff.lint.mccabe]
+max-complexity = 5
+
 
 
diff --git a/src/gui_2.py b/src/gui_2.py
index 91baec8..c272f1b 100644
--- a/src/gui_2.py
+++ b/src/gui_2.py
@@ -779,13 +779,11 @@ class App:
   [C: tests/test_shader_live_editor.py:test_shader_live_editor_renders]
   """
   if self.show_windows.get('Shader Editor', False):
-   exp, opened = imgui.begin('Shader Editor', self.show_windows['Shader Editor'])
-   self.show_windows['Shader Editor'] = bool(opened)
-   if exp:
-    changed_crt, self.shader_uniforms['crt'] = imgui.slider_float('CRT Curvature', self.shader_uniforms['crt'], 0.0, 2.0)
-    changed_scan, self.shader_uniforms['scanline'] = imgui.slider_float('Scanline Intensity', self.shader_uniforms['scanline'], 0.0, 1.0)
-    changed_bloom, self.shader_uniforms['bloom'] = imgui.slider_float('Bloom Threshold', self.shader_uniforms['bloom'], 0.0, 1.0)
-   imgui.end()
+   with imgui_window('Shader Editor', self.show_windows['Shader Editor']) as window_result:
+    if window_result:
+     changed_crt, self.shader_uniforms['crt'] = imgui.slider_float('CRT Curvature', self.shader_uniforms['crt'], 0.0, 2.0)
+     changed_scan, self.shader_uniforms['scanline'] = imgui.slider_float('Scanline Intensity', self.shader_uniforms['scanline'], 0.0, 1.0)
+     changed_bloom, self.shader_uniforms['bloom'] = imgui.slider_float('Bloom Threshold', self.shader_uniforms['bloom'], 0.0, 1.0)
 
  def _render_history_window(self) -> None:
   if not self.show_windows.get('Undo/Redo History', False):
diff --git a/src/imgui_scopes.py b/src/imgui_scopes.py
index 9be3407..88a4be1 100644
--- a/src/imgui_scopes.py
+++ b/src/imgui_scopes.py
@@ -20,13 +20,13 @@ class ImGuiScope:
   self._entered = False
 
  def __enter__(self) -> bool | tuple:
-  result = self._begin_fn(*self._args, **self._kwargs)
-  if isinstance(result, tuple):
-   self._opened = result[0]
+  self._opened = self._begin_fn(*self._args, **self._kwargs)
+  if isinstance(self._opened, tuple):
+   self._entered = bool(self._opened[0])
+   return self._opened
   else:
-   self._opened = result
-  self._entered = bool(self._opened)
-  return self._opened
+   self._entered = bool(self._opened)
+   return self._opened
 
  def __exit__(self, *args: object) -> bool:
   if self._entered: