diff --git a/src/renderer/components/extensions/skills/SkillEditorDialog.tsx b/src/renderer/components/extensions/skills/SkillEditorDialog.tsx
index d063bc69..1b0cb3a3 100644
--- a/src/renderer/components/extensions/skills/SkillEditorDialog.tsx
+++ b/src/renderer/components/extensions/skills/SkillEditorDialog.tsx
@@ -730,6 +730,7 @@ export const SkillEditorDialog = ({
                           size="sm"
                           onClick={() => {
                             setManualRawEdit(false);
+                            setCustomMarkdownDetected(false);
                             const nextRawContent = buildSkillTemplate({
                               name,
                               description,
diff --git a/test/renderer/components/extensions/skills/SkillEditorDialog.test.ts b/test/renderer/components/extensions/skills/SkillEditorDialog.test.ts
new file mode 100644
index 00000000..72cce57a
--- /dev/null
+++ b/test/renderer/components/extensions/skills/SkillEditorDialog.test.ts
@@ -0,0 +1,245 @@
+import React, { act } from 'react';
+import { createRoot } from 'react-dom/client';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+import type { SkillDetail } from '@shared/types/extensions';
+
+interface StoreState {
+  previewSkillUpsert: ReturnType<typeof vi.fn>;
+  applySkillUpsert: ReturnType<typeof vi.fn>;
+}
+
+const storeState = {} as StoreState;
+
+vi.mock('@renderer/store', () => ({
+  useStore: (selector: (state: StoreState) => unknown) => selector(storeState),
+}));
+
+vi.mock('@renderer/hooks/useMarkdownScrollSync', () => ({
+  useMarkdownScrollSync: () => ({
+    handleCodeScroll: vi.fn(),
+    handlePreviewScroll: vi.fn(),
+    previewScrollRef: { current: null },
+  }),
+}));
+
+vi.mock('@renderer/components/team/editor/MarkdownPreviewPane', () => ({
+  MarkdownPreviewPane: () => React.createElement('div', null, 'Preview'),
+}));
+
+vi.mock('@renderer/components/ui/badge', () => ({
+  Badge: ({ children }: React.PropsWithChildren) => React.createElement('span', null, children),
+}));
+
+vi.mock('@renderer/components/ui/button', () => ({
+  Button: ({
+    children,
+    onClick,
+    type = 'button',
+    disabled,
+  }: React.PropsWithChildren<{
+    onClick?: () => void;
+    type?: 'button' | 'submit' | 'reset';
+    disabled?: boolean;
+  }>) =>
+    React.createElement(
+      'button',
+      {
+        type,
+        disabled,
+        onClick,
+      },
+      children
+    ),
+}));
+
+vi.mock('@renderer/components/ui/checkbox', () => ({
+  Checkbox: ({
+    checked,
+    onCheckedChange,
+  }: {
+    checked?: boolean;
+    onCheckedChange?: (value: boolean) => void;
+    className?: string;
+  }) =>
+    React.createElement('input', {
+      type: 'checkbox',
+      checked,
+      onChange: (event: React.ChangeEvent<HTMLInputElement>) =>
+        onCheckedChange?.(event.target.checked),
+    }),
+}));
+
+vi.mock('@renderer/components/ui/dialog', () => ({
+  Dialog: ({ open, children }: React.PropsWithChildren<{ open: boolean }>) =>
+    open ? React.createElement('div', null, children) : null,
+  DialogContent: ({ children }: React.PropsWithChildren) => React.createElement('div', null, children),
+  DialogDescription: ({ children }: React.PropsWithChildren) =>
+    React.createElement('p', null, children),
+  DialogHeader: ({ children }: React.PropsWithChildren) => React.createElement('div', null, children),
+  DialogTitle: ({ children }: React.PropsWithChildren) => React.createElement('h2', null, children),
+}));
+
+vi.mock('@renderer/components/ui/input', () => ({
+  Input: (props: React.InputHTMLAttributes<HTMLInputElement>) =>
+    React.createElement('input', props),
+}));
+
+vi.mock('@renderer/components/ui/label', () => ({
+  Label: ({ children, htmlFor }: React.PropsWithChildren<{ htmlFor?: string }>) =>
+    React.createElement('label', { htmlFor }, children),
+}));
+
+vi.mock('@renderer/components/ui/select', () => ({
+  Select: ({
+    children,
+    value,
+    onValueChange,
+    disabled,
+  }: React.PropsWithChildren<{
+    value: string;
+    onValueChange: (value: string) => void;
+    disabled?: boolean;
+  }>) =>
+    React.createElement(
+      'select',
+      {
+        value,
+        disabled,
+        onChange: (event: React.ChangeEvent<HTMLSelectElement>) => onValueChange(event.target.value),
+      },
+      children
+    ),
+  SelectTrigger: () => null,
+  SelectValue: () => null,
+  SelectContent: ({ children }: React.PropsWithChildren) =>
+    React.createElement(React.Fragment, null, children),
+  SelectItem: ({
+    children,
+    value,
+    disabled,
+  }: React.PropsWithChildren<{ value: string; disabled?: boolean }>) =>
+    React.createElement('option', { value, disabled }, children),
+}));
+
+vi.mock('@renderer/components/ui/textarea', () => ({
+  Textarea: (props: React.TextareaHTMLAttributes<HTMLTextAreaElement>) =>
+    React.createElement('textarea', props),
+}));
+
+vi.mock('@renderer/components/extensions/skills/SkillCodeEditor', () => ({
+  SkillCodeEditor: () => React.createElement('div', null, 'Editor'),
+}));
+
+vi.mock('@renderer/components/extensions/skills/SkillReviewDialog', () => ({
+  SkillReviewDialog: () => null,
+}));
+
+vi.mock('lucide-react', () => {
+  const Icon = (props: React.SVGProps<SVGSVGElement>) => React.createElement('svg', props);
+  return {
+    FileSearch: Icon,
+    RotateCcw: Icon,
+    X: Icon,
+  };
+});
+
+import { SkillEditorDialog } from '@renderer/components/extensions/skills/SkillEditorDialog';
+
+function makeDetail(rawContent: string): SkillDetail {
+  return {
+    item: {
+      id: '/tmp/project/.claude/skills/custom-skill',
+      sourceType: 'filesystem',
+      name: 'Custom Skill',
+      description: 'Custom markdown skill',
+      folderName: 'custom-skill',
+      scope: 'project',
+      rootKind: 'claude',
+      projectRoot: '/tmp/project',
+      discoveryRoot: '/tmp/project/.claude/skills',
+      skillDir: '/tmp/project/.claude/skills/custom-skill',
+      skillFile: '/tmp/project/.claude/skills/custom-skill/SKILL.md',
+      metadata: {},
+      invocationMode: 'auto',
+      flags: {
+        hasScripts: false,
+        hasReferences: false,
+        hasAssets: false,
+      },
+      isValid: true,
+      issues: [],
+      modifiedAt: 1,
+    },
+    body: rawContent,
+    rawContent,
+    rawFrontmatter: null,
+    referencesFiles: [],
+    scriptFiles: [],
+    assetFiles: [],
+  };
+}
+
+describe('SkillEditorDialog', () => {
+  beforeEach(() => {
+    vi.stubGlobal('IS_REACT_ACT_ENVIRONMENT', true);
+    storeState.previewSkillUpsert = vi.fn();
+    storeState.applySkillUpsert = vi.fn();
+  });
+
+  afterEach(() => {
+    document.body.innerHTML = '';
+    vi.unstubAllGlobals();
+  });
+
+  it('unlocks structured editing after resetting a custom markdown skill', async () => {
+    const host = document.createElement('div');
+    document.body.appendChild(host);
+    const root = createRoot(host);
+    const detail = makeDetail(`---
+name: Custom Skill
+description: Custom markdown skill
+---
+
+# Custom Skill
+
+This file uses a freeform layout without generated sections.
+`);
+
+    await act(async () => {
+      root.render(
+        React.createElement(SkillEditorDialog, {
+          open: true,
+          mode: 'edit',
+          projectPath: '/tmp/project',
+          projectLabel: 'Project',
+          detail,
+          onClose: vi.fn(),
+          onSaved: vi.fn(),
+        })
+      );
+      await Promise.resolve();
+    });
+
+    expect(host.querySelector('#skill-when-to-use')).toBeNull();
+
+    const resetButton = Array.from(host.querySelectorAll('button')).find((button) =>
+      button.textContent?.includes('Reset From Structured Fields')
+    ) as HTMLButtonElement;
+    expect(resetButton).toBeDefined();
+
+    await act(async () => {
+      resetButton.click();
+      await Promise.resolve();
+    });
+
+    const whenToUseField = host.querySelector('#skill-when-to-use') as HTMLTextAreaElement;
+    expect(whenToUseField).not.toBeNull();
+    expect(whenToUseField.disabled).toBe(false);
+
+    await act(async () => {
+      root.unmount();
+      await Promise.resolve();
+    });
+  });
+});