diff --git a/Packages/vChewing_CocoaExtension/Sources/CocoaExtension/CocoaExtension_NSView.swift b/Packages/vChewing_CocoaExtension/Sources/CocoaExtension/CocoaExtension_NSView.swift
new file mode 100644
index 00000000..f9c5d4e0
--- /dev/null
+++ b/Packages/vChewing_CocoaExtension/Sources/CocoaExtension/CocoaExtension_NSView.swift
@@ -0,0 +1,396 @@
+// (c) 2022 and onwards The vChewing Project (MIT-NTL License).
+// ====================
+// This code is released under the MIT license (SPDX-License-Identifier: MIT)
+// ... with NTL restriction stating that:
+// No trademark license is granted to use the trade names, trademarks, service
+// marks, or product names of Contributor, except as required to fulfill notice
+// requirements defined in MIT License.
+
+import AppKit
+import SwiftExtension
+
+// MARK: - NSAlert
+
+public extension NSAlert {
+  func beginSheetModal(at window: NSWindow?, completionHandler handler: @escaping (NSApplication.ModalResponse) -> Void) {
+    if let window = window ?? NSApp.keyWindow {
+      beginSheetModal(for: window, completionHandler: handler)
+    } else {
+      handler(runModal())
+    }
+  }
+}
+
+// MARK: - NSOpenPanel
+
+public extension NSOpenPanel {
+  func beginSheetModal(at window: NSWindow?, completionHandler handler: @escaping (NSApplication.ModalResponse) -> Void) {
+    if let window = window ?? NSApp.keyWindow {
+      beginSheetModal(for: window, completionHandler: handler)
+    } else {
+      handler(runModal())
+    }
+  }
+}
+
+// MARK: - NSButton
+
+public extension NSButton {
+  convenience init(verbatim title: String, target: AnyObject?, action: Selector?) {
+    self.init()
+    self.title = title
+    self.target = target
+    self.action = action
+    bezelStyle = .rounded
+  }
+
+  convenience init(_ title: String, target: AnyObject?, action: Selector?) {
+    self.init(verbatim: title.localized, target: target, action: action)
+  }
+}
+
+// MARK: - Convenient Constructor for NSEdgeInsets.
+
+public extension NSEdgeInsets {
+  static func new(all: CGFloat? = nil, top: CGFloat? = nil, bottom: CGFloat? = nil, left: CGFloat? = nil, right: CGFloat? = nil) -> NSEdgeInsets {
+    NSEdgeInsets(top: top ?? all ?? 0, left: left ?? all ?? 0, bottom: bottom ?? all ?? 0, right: right ?? all ?? 0)
+  }
+}
+
+// MARK: - Constrains and Box Container Modifier.
+
+public extension NSView {
+  @discardableResult func makeSimpleConstraint(
+    _ attribute: NSLayoutConstraint.Attribute,
+    relation: NSLayoutConstraint.Relation,
+    value: CGFloat?
+  ) -> NSView {
+    guard let value = value else { return self }
+    translatesAutoresizingMaskIntoConstraints = false
+    let widthConstraint = NSLayoutConstraint(
+      item: self, attribute: attribute, relatedBy: relation, toItem: nil,
+      attribute: NSLayoutConstraint.Attribute.notAnAttribute, multiplier: 1, constant: value
+    )
+    addConstraint(widthConstraint)
+    return self
+  }
+
+  func boxed(title: String = "") -> NSBox {
+    let maxDimension = fittingSize
+    let result = NSBox()
+    result.title = title.localized
+    if result.title.isEmpty {
+      result.titlePosition = .noTitle
+    }
+    let minWidth = Swift.max(maxDimension.width + 12, result.intrinsicContentSize.width)
+    let minHeight = Swift.max(maxDimension.height + result.titleRect.height + 14, result.intrinsicContentSize.height)
+    result.makeSimpleConstraint(.width, relation: .greaterThanOrEqual, value: minWidth)
+    result.makeSimpleConstraint(.height, relation: .greaterThanOrEqual, value: minHeight)
+    result.contentView = self
+    if let self = self as? NSStackView, self.orientation == .horizontal {
+      self.spacing = 0
+    }
+    return result
+  }
+}
+
+// MARK: - Stacks
+
+public extension NSStackView {
+  var requiresConstraintBasedLayout: Bool {
+    true
+  }
+
+  static func buildSection(
+    _ orientation: NSUserInterfaceLayoutOrientation = .vertical,
+    width: CGFloat? = nil,
+    withDividers: Bool = true,
+    @ArrayBuilder<NSView?> views: () -> [NSView?]
+  ) -> NSStackView? {
+    let viewsRendered = views().compactMap {
+      // 下述註解是用來協助偵錯的。
+      // $0?.wantsLayer = true
+      // $0?.layer?.backgroundColor = NSColor.red.cgColor
+      $0
+    }
+    guard !viewsRendered.isEmpty else { return nil }
+    var itemWidth = width
+    var splitterDelta: CGFloat = 4
+    splitterDelta = withDividers ? splitterDelta : 0
+    if let width = width, orientation == .horizontal, viewsRendered.count > 0 {
+      itemWidth = (width - splitterDelta) / CGFloat(viewsRendered.count) - 6
+    }
+    func giveViews() -> [NSView?] { viewsRendered }
+    let result = build(orientation, divider: withDividers, width: itemWidth, views: giveViews)?
+      .withInsets(.new(all: 4))
+    return result
+  }
+
+  static func build(
+    _ orientation: NSUserInterfaceLayoutOrientation,
+    divider: Bool = false,
+    width: CGFloat? = nil,
+    height: CGFloat? = nil,
+    insets: NSEdgeInsets? = nil,
+    @ArrayBuilder<NSView?> views: () -> [NSView?]
+  ) -> NSStackView? {
+    let result = views().compactMap {
+      $0?
+        .makeSimpleConstraint(.width, relation: .equal, value: width)
+        .makeSimpleConstraint(.height, relation: .equal, value: height)
+    }
+    guard !result.isEmpty else { return nil }
+    return result.stack(orientation, divider: divider)?.withInsets(insets)
+  }
+
+  func withInsets(_ newValue: NSEdgeInsets?) -> NSStackView {
+    edgeInsets = newValue ?? edgeInsets
+    return self
+  }
+}
+
+public extension Array where Element == NSView {
+  func stack(
+    _ orientation: NSUserInterfaceLayoutOrientation,
+    divider: Bool = false,
+    insets: NSEdgeInsets? = nil
+  ) -> NSStackView? {
+    guard !isEmpty else { return nil }
+    let outerStack = NSStackView()
+    if #unavailable(macOS 10.11) {
+      outerStack.hasEqualSpacing = true
+    } else {
+      outerStack.distribution = .equalSpacing
+    }
+    outerStack.orientation = orientation
+
+    if #unavailable(macOS 10.10) {
+      outerStack.spacing = Swift.max(1, outerStack.spacing) - 1
+    }
+
+    outerStack.setHuggingPriority(.fittingSizeCompression, for: .horizontal)
+    outerStack.setHuggingPriority(.fittingSizeCompression, for: .vertical)
+
+    forEach { subView in
+      if divider, !outerStack.views.isEmpty {
+        let divider = NSView()
+        divider.wantsLayer = true
+        divider.layer?.backgroundColor = NSColor.gray.withAlphaComponent(0.2).cgColor
+        switch orientation {
+        case .horizontal:
+          divider.makeSimpleConstraint(.width, relation: .equal, value: 1)
+        case .vertical:
+          divider.makeSimpleConstraint(.height, relation: .equal, value: 1)
+        @unknown default: break
+        }
+        divider.translatesAutoresizingMaskIntoConstraints = false
+        outerStack.addView(divider, in: orientation == .horizontal ? .leading : .top)
+      }
+      subView.layoutSubtreeIfNeeded()
+      switch orientation {
+      case .horizontal:
+        subView.makeSimpleConstraint(.height, relation: .greaterThanOrEqual, value: subView.intrinsicContentSize.height)
+        subView.makeSimpleConstraint(.width, relation: .greaterThanOrEqual, value: subView.intrinsicContentSize.width)
+      case .vertical:
+        subView.makeSimpleConstraint(.width, relation: .greaterThanOrEqual, value: subView.intrinsicContentSize.width)
+        subView.makeSimpleConstraint(.height, relation: .greaterThanOrEqual, value: subView.intrinsicContentSize.height)
+      @unknown default: break
+      }
+      subView.setContentCompressionResistancePriority(.defaultHigh, for: .horizontal)
+      subView.setContentCompressionResistancePriority(.defaultHigh, for: .vertical)
+      subView.translatesAutoresizingMaskIntoConstraints = false
+      outerStack.addView(subView, in: orientation == .horizontal ? .leading : .top)
+    }
+
+    switch orientation {
+    case .horizontal:
+      outerStack.alignment = .centerY
+    case .vertical:
+      outerStack.alignment = .leading
+    @unknown default: break
+    }
+    return outerStack.withInsets(insets)
+  }
+}
+
+// MARK: - Make NSAttributedString into Label
+
+public extension NSAttributedString {
+  func makeNSLabel(fixWidth: CGFloat? = nil) -> NSTextField {
+    let textField = NSTextField()
+    textField.attributedStringValue = self
+    textField.isEditable = false
+    textField.isBordered = false
+    textField.backgroundColor = .clear
+    if let fixWidth = fixWidth {
+      textField.preferredMaxLayoutWidth = fixWidth
+    }
+    return textField
+  }
+}
+
+// MARK: - Make String into Label
+
+public extension String {
+  func makeNSLabel(descriptive: Bool = false, localized: Bool = true, fixWidth: CGFloat? = nil) -> NSTextField {
+    let rawAttributedString = NSMutableAttributedString(string: localized ? self.localized : self)
+    rawAttributedString.addAttributes([.kern: 0], range: .init(location: 0, length: rawAttributedString.length))
+    let textField = rawAttributedString.makeNSLabel(fixWidth: fixWidth)
+    if descriptive {
+      if #available(macOS 10.10, *) {
+        textField.textColor = .secondaryLabelColor
+      } else {
+        textField.textColor = .textColor.withAlphaComponent(0.55)
+      }
+      textField.font = NSFont.systemFont(ofSize: NSFont.smallSystemFontSize)
+    }
+    return textField
+  }
+}
+
+// MARK: - NSTabView
+
+public extension NSTabView {
+  struct TabPage {
+    public let title: String
+    public let view: NSView
+
+    public init?(title: String, view: NSView?) {
+      self.title = title
+      guard let view = view else { return nil }
+      self.view = view
+    }
+
+    public init(title: String, view: NSView) {
+      self.title = title
+      self.view = view
+    }
+
+    public init?(title: String, @ArrayBuilder<NSView?> views: () -> [NSView?]) {
+      self.title = title
+      let viewsRendered = views()
+      guard !viewsRendered.isEmpty else { return nil }
+      func giveViews() -> [NSView?] { viewsRendered }
+      let result = NSStackView.build(.vertical, insets: .new(all: 14, top: 0), views: giveViews)
+      guard let result = result else { return nil }
+      view = result
+    }
+  }
+
+  static func build(
+    @ArrayBuilder<TabPage?> pages: () -> [TabPage?]
+  ) -> NSTabView? {
+    let tabPages = pages().compactMap { $0 }
+    guard !tabPages.isEmpty else { return nil }
+    let finalTabView = NSTabView()
+    tabPages.forEach { currentPage in
+      finalTabView.addTabViewItem({
+        let currentItem = NSTabViewItem(identifier: UUID())
+        currentItem.label = currentPage.title.localized
+        let stacked = NSStackView.build(.vertical) {
+          currentPage.view
+        }
+        stacked?.alignment = .centerX
+        currentItem.view = stacked
+        return currentItem
+      }())
+    }
+    return finalTabView
+  }
+}
+
+// MARK: - NSMenu
+
+public extension NSMenu {
+  @discardableResult func appendItems(_ target: AnyObject? = nil, @ArrayBuilder<NSMenuItem?> items: () -> [NSMenuItem?]) -> NSMenu {
+    let theItems = items()
+    for currentItem in theItems {
+      guard let currentItem = currentItem else { continue }
+      addItem(currentItem)
+      guard let target = target else { continue }
+      currentItem.target = target
+      currentItem.submenu?.propagateTarget(target)
+    }
+    return self
+  }
+
+  @discardableResult func propagateTarget(_ obj: AnyObject?) -> NSMenu {
+    for currentItem in items {
+      currentItem.target = obj
+      currentItem.submenu?.propagateTarget(obj)
+    }
+    return self
+  }
+
+  static func buildSubMenu(verbatim: String?, @ArrayBuilder<NSMenuItem?> items: () -> [NSMenuItem?]) -> NSMenuItem? {
+    guard let verbatim = verbatim, !verbatim.isEmpty else { return nil }
+    let newItem = NSMenu.Item(verbatim: verbatim)
+    newItem?.submenu = .init(title: verbatim).appendItems(items: items)
+    return newItem
+  }
+
+  static func buildSubMenu(_ title: String?, @ArrayBuilder<NSMenuItem?> items: () -> [NSMenuItem?]) -> NSMenuItem? {
+    guard let title = title?.localized, !title.isEmpty else { return nil }
+    return buildSubMenu(verbatim: title, items: items)
+  }
+
+  typealias Item = NSMenuItem
+}
+
+public extension Array where Element == NSMenuItem? {
+  func propagateTarget(_ obj: AnyObject?) {
+    forEach { currentItem in
+      guard let currentItem = currentItem else { return }
+      currentItem.target = obj
+      currentItem.submenu?.propagateTarget(obj)
+    }
+  }
+}
+
+public extension NSMenuItem {
+  convenience init?(verbatim: String?) {
+    guard let verbatim = verbatim, !verbatim.isEmpty else { return nil }
+    self.init(title: verbatim, action: nil, keyEquivalent: "")
+  }
+
+  convenience init?(_ title: String?) {
+    guard let title = title?.localized, !title.isEmpty else { return nil }
+    self.init(verbatim: title)
+  }
+
+  @discardableResult func hotkey(_ keyEquivalent: String, mask: NSEvent.ModifierFlags? = nil) -> NSMenuItem {
+    keyEquivalentModifierMask = mask ?? keyEquivalentModifierMask
+    self.keyEquivalent = keyEquivalent
+    return self
+  }
+
+  @discardableResult func state(_ givenState: Bool) -> NSMenuItem {
+    state = givenState ? .on : .off
+    return self
+  }
+
+  @discardableResult func act(_ action: Selector) -> NSMenuItem {
+    self.action = action
+    return self
+  }
+
+  @discardableResult func nulled(_ condition: Bool) -> NSMenuItem? {
+    condition ? nil : self
+  }
+
+  @discardableResult func mask(_ flags: NSEvent.ModifierFlags) -> NSMenuItem {
+    keyEquivalentModifierMask = flags
+    return self
+  }
+
+  @discardableResult func represent(_ object: Any?) -> NSMenuItem {
+    representedObject = object
+    return self
+  }
+
+  @discardableResult func tag(_ givenTag: Int?) -> NSMenuItem {
+    guard let givenTag = givenTag else { return self }
+    tag = givenTag
+    return self
+  }
+}
diff --git a/Packages/vChewing_CocoaExtension/Sources/CocoaExtension/CocoaExtension_NSWindowController.swift b/Packages/vChewing_CocoaExtension/Sources/CocoaExtension/CocoaExtension_NSWindowController.swift
index 8e10fa81..94296827 100644
--- a/Packages/vChewing_CocoaExtension/Sources/CocoaExtension/CocoaExtension_NSWindowController.swift
+++ b/Packages/vChewing_CocoaExtension/Sources/CocoaExtension/CocoaExtension_NSWindowController.swift
@@ -48,12 +48,19 @@ public extension NSWindowController {
 }
 
 public extension NSWindow {
+  @discardableResult func callAlert(title: String, text: String? = nil) -> NSApplication.ModalResponse {
+    (self as NSWindow?).callAlert(title: title, text: text)
+  }
+}
+
+public extension NSWindow? {
   @discardableResult func callAlert(title: String, text: String? = nil) -> NSApplication.ModalResponse {
     let alert = NSAlert()
     alert.messageText = title
     if let text = text { alert.informativeText = text }
     alert.addButton(withTitle: NSLocalizedString("OK", comment: ""))
     var result: NSApplication.ModalResponse = .alertFirstButtonReturn
+    guard let self = self else { return alert.runModal() }
     alert.beginSheetModal(for: self) { theResponce in
       result = theResponce
     }
diff --git a/Packages/vChewing_Shared/Sources/Shared/UserDef.swift b/Packages/vChewing_Shared/Sources/Shared/UserDef/UserDef.swift
similarity index 99%
rename from Packages/vChewing_Shared/Sources/Shared/UserDef.swift
rename to Packages/vChewing_Shared/Sources/Shared/UserDef/UserDef.swift
index 819250b2..ec1db823 100644
--- a/Packages/vChewing_Shared/Sources/Shared/UserDef.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/UserDef/UserDef.swift
@@ -20,7 +20,6 @@ public enum UserDef: String, CaseIterable, Identifiable {
   public struct MetaData {
     public var userDef: UserDef
     public var shortTitle: String?
-    public var control: AnyObject?
     public var prompt: String?
     public var inlinePrompt: String?
     public var popupPrompt: String?
diff --git a/Packages/vChewing_Shared/Sources/Shared/UserDefRenderable.swift b/Packages/vChewing_Shared/Sources/Shared/UserDef/UserDefRenderable.swift
similarity index 100%
rename from Packages/vChewing_Shared/Sources/Shared/UserDefRenderable.swift
rename to Packages/vChewing_Shared/Sources/Shared/UserDef/UserDefRenderable.swift
diff --git a/Packages/vChewing_Shared/Sources/Shared/UserDef/UserDefRenderableCocoa.swift b/Packages/vChewing_Shared/Sources/Shared/UserDef/UserDefRenderableCocoa.swift
new file mode 100644
index 00000000..f1d60a2c
--- /dev/null
+++ b/Packages/vChewing_Shared/Sources/Shared/UserDef/UserDefRenderableCocoa.swift
@@ -0,0 +1,275 @@
+// (c) 2022 and onwards The vChewing Project (MIT-NTL License).
+// ====================
+// This code is released under the MIT license (SPDX-License-Identifier: MIT)
+// ... with NTL restriction stating that:
+// No trademark license is granted to use the trade names, trademarks, service
+// marks, or product names of Contributor, except as required to fulfill notice
+// requirements defined in MIT License.
+
+// 這其實是 UserDefRenderable 的另一個版本，但用的是 AppKit 而非 SwiftUI。
+
+import AppKit
+import CocoaExtension
+import Foundation
+import IMKUtils
+
+public class UserDefRenderableCocoa: NSObject, Identifiable {
+  public let def: UserDef
+  public var id: String { def.rawValue }
+  public var optionsLocalized: [(Int, String)?]
+  private var optionsLocalizedAsIdentifiables: [(String, String)?] = [] // 非 Int 型資料專用（例：鍵盤佈局選擇器）。
+  public var inlineDescriptionLocalized: String?
+  public var hideTitle: Bool = false
+  public var mainViewOverride: (() -> NSView?)?
+  public var currentControl: NSControl?
+  public var tinySize: Bool = false
+
+  public init(def: UserDef) {
+    self.def = def
+    if let rawOptions = def.metaData?.options, !rawOptions.isEmpty {
+      var newOptions: [Int: String] = [:]
+      rawOptions.forEach { key, value in
+        newOptions[key] = value.localized
+      }
+      optionsLocalized = rawOptions.sorted(by: { $0.key < $1.key })
+    } else {
+      optionsLocalized = []
+    }
+
+    var objOptions = [(String, String)?]()
+    var intOptions = [(Int, String)?]()
+    checkDef: switch def {
+    case .kAlphanumericalKeyboardLayout:
+      IMKHelper.allowedAlphanumericalTISInputSources.forEach { currentTIS in
+        objOptions.append((currentTIS.identifier, currentTIS.vChewingLocalizedName))
+      }
+      optionsLocalizedAsIdentifiables = objOptions
+    case .kBasicKeyboardLayout:
+      IMKHelper.allowedBasicLayoutsAsTISInputSources.forEach { currentTIS in
+        guard let currentTIS = currentTIS else {
+          objOptions.append(nil)
+          return
+        }
+        objOptions.append((currentTIS.identifier, currentTIS.vChewingLocalizedName))
+      }
+      optionsLocalizedAsIdentifiables = objOptions
+    case .kKeyboardParser:
+      KeyboardParser.allCases.forEach { currentParser in
+        if [7, 100].contains(currentParser.rawValue) { intOptions.append(nil) }
+        intOptions.append((currentParser.rawValue, currentParser.localizedMenuName))
+      }
+      optionsLocalized = intOptions
+    default: break checkDef
+    }
+
+    super.init()
+    guard let metaData = def.metaData else {
+      inlineDescriptionLocalized = nil
+      return
+    }
+    var stringStack = [String]()
+    if let promptText = metaData.inlinePrompt?.localized, !promptText.isEmpty {
+      stringStack.append(promptText)
+    }
+    if let descText = metaData.description?.localized, !descText.isEmpty {
+      stringStack.append(descText)
+    }
+    if metaData.minimumOS > 10.9 {
+      var strOSReq = " "
+      strOSReq += String(
+        format: "This feature requires macOS %@ and above.".localized, arguments: ["12.0"]
+      )
+      stringStack.append(strOSReq)
+    }
+    currentControl = renderFunctionControl()
+    guard !stringStack.isEmpty else {
+      inlineDescriptionLocalized = nil
+      return
+    }
+    inlineDescriptionLocalized = stringStack.joined(separator: "\n")
+  }
+}
+
+public extension UserDefRenderableCocoa {
+  func render(fixWidth fixedWith: CGFloat? = nil) -> NSView? {
+    let result: NSStackView? = NSStackView.build(.vertical) {
+      renderMainLine(fixedWidth: fixedWith)
+      renderDescription(fixedWidth: fixedWith)
+    }
+    result?.makeSimpleConstraint(.width, relation: .equal, value: fixedWith)
+    return result
+  }
+
+  func renderDescription(fixedWidth: CGFloat? = nil) -> NSTextField? {
+    guard let text = inlineDescriptionLocalized else { return nil }
+    let textField = text.makeNSLabel(descriptive: true)
+    if #available(macOS 10.10, *), tinySize {
+      textField.controlSize = .small
+      textField.font = NSFont.systemFont(ofSize: NSFont.smallSystemFontSize)
+    }
+    textField.preferredMaxLayoutWidth = fixedWidth ?? 0
+    return textField
+  }
+
+  func renderMainLine(fixedWidth: CGFloat? = nil) -> NSView? {
+    if let mainViewOverride = mainViewOverride {
+      return mainViewOverride()
+    }
+    guard let control: NSView = currentControl ?? renderFunctionControl() else { return nil }
+    let controlWidth = control.fittingSize.width
+    let textLabel: NSTextField? = {
+      if !hideTitle, let strTitle = def.metaData?.shortTitle {
+        return strTitle.makeNSLabel()
+      }
+      return nil
+    }()
+    let result = NSStackView.build(.horizontal) {
+      if !hideTitle, let textlabel = textLabel {
+        textlabel
+        NSView()
+      }
+      control
+    }
+    if let fixedWidth = fixedWidth {
+      textLabel?.preferredMaxLayoutWidth = fixedWidth - controlWidth
+    }
+    textLabel?.sizeToFit()
+    return result
+  }
+
+  private func renderFunctionControl() -> NSControl? {
+    var result: NSControl? {
+      switch def.dataType {
+      case .string where def == .kCandidateKeys:
+        let comboBox = NSComboBox()
+        comboBox.makeSimpleConstraint(.width, relation: .equal, value: 128)
+        comboBox.font = NSFont.systemFont(ofSize: 12)
+        comboBox.intercellSpacing = NSSize(width: 0.0, height: 10.0)
+        comboBox.addItems(withObjectValues: CandidateKey.suggestions)
+        comboBox.bind(
+          .value,
+          to: NSUserDefaultsController.shared,
+          withKeyPath: "values.\(def.rawValue)"
+        )
+        return comboBox
+      case .bool where optionsLocalized.isEmpty:
+        let checkBox: NSControl
+        if #unavailable(macOS 10.15) {
+          checkBox = NSButton()
+          (checkBox as? NSButton)?.setButtonType(.switch)
+          (checkBox as? NSButton)?.title = ""
+        } else {
+          checkBox = NSSwitch()
+          checkBox.controlSize = .mini
+        }
+        checkBox.bind(
+          .value,
+          to: NSUserDefaultsController.shared,
+          withKeyPath: "values.\(def.rawValue)",
+          options: [.continuouslyUpdatesValue: true]
+        )
+
+        // 特殊情形開始：部分控件有啟用條件，條件不滿足則變灰。
+        checkDef: switch def {
+        case .kAlwaysExpandCandidateWindow:
+          checkBox.bind(
+            .enabled,
+            to: NSUserDefaultsController.shared,
+            withKeyPath: "values.\(UserDef.kCandidateWindowShowOnlyOneLine.rawValue)",
+            options: [
+              .valueTransformerName: NSValueTransformerName.negateBooleanTransformerName,
+            ]
+          )
+        case .kUseDynamicCandidateWindowOrigin:
+          checkBox.bind(
+            .enabled,
+            to: NSUserDefaultsController.shared,
+            withKeyPath: "values.\(UserDef.kUseRearCursorMode.rawValue)",
+            options: [
+              .valueTransformerName: NSValueTransformerName.negateBooleanTransformerName,
+            ]
+          )
+        default: break checkDef
+        }
+        // 特殊情形結束
+
+        return checkBox
+      case .integer, .double,
+           .bool where !optionsLocalized.isEmpty,
+           .string where !optionsLocalized.isEmpty,
+           .string where !optionsLocalizedAsIdentifiables.isEmpty:
+        let dropMenu: NSMenu = .init()
+        let btnPopup = NSPopUpButton()
+        var itemShouldBeChosen: NSMenuItem?
+        if !optionsLocalizedAsIdentifiables.isEmpty {
+          btnPopup.bind(
+            .selectedObject,
+            to: NSUserDefaultsController.shared,
+            withKeyPath: "values.\(def.rawValue)",
+            options: [.continuouslyUpdatesValue: true]
+          )
+          optionsLocalizedAsIdentifiables.forEach { entity in
+            guard let obj = entity?.0, let title = entity?.1.localized else {
+              dropMenu.addItem(.separator())
+              return
+            }
+            let newItem = NSMenuItem(title: title, action: nil, keyEquivalent: "")
+            newItem.representedObject = .init(obj)
+            if obj == UserDefaults.current.object(forKey: def.rawValue) as? String {
+              itemShouldBeChosen = newItem
+            }
+            dropMenu.addItem(newItem)
+          }
+        } else {
+          btnPopup.bind(
+            .selectedTag,
+            to: NSUserDefaultsController.shared,
+            withKeyPath: "values.\(def.rawValue)",
+            options: [.continuouslyUpdatesValue: true]
+          )
+          optionsLocalized.forEach { entity in
+            guard let tag = entity?.0, let title = entity?.1.localized else {
+              dropMenu.addItem(.separator())
+              return
+            }
+            let newItem = NSMenuItem(title: title, action: nil, keyEquivalent: "")
+            newItem.tag = tag
+            if tag == UserDefaults.current.integer(forKey: def.rawValue) {
+              itemShouldBeChosen = newItem
+            }
+            if Double(tag) == UserDefaults.current.double(forKey: def.rawValue) {
+              itemShouldBeChosen = newItem
+            }
+            dropMenu.addItem(newItem)
+          }
+        }
+        btnPopup.menu = dropMenu
+        btnPopup.font = NSFont.systemFont(ofSize: 12)
+        btnPopup.setFrameSize(btnPopup.fittingSize)
+        btnPopup.select(itemShouldBeChosen)
+        return btnPopup
+      case .array, .dictionary, .other: return nil
+      default: return nil
+      }
+    }
+    if #available(macOS 10.10, *), tinySize {
+      result?.controlSize = .small
+      return result?.makeSimpleConstraint(.height, relation: .greaterThanOrEqual, value: Swift.max(14, result?.fittingSize.height ?? 14)) as? NSControl
+    }
+    return result?.makeSimpleConstraint(.height, relation: .greaterThanOrEqual, value: Swift.max(16, result?.fittingSize.height ?? 16)) as? NSControl
+  }
+}
+
+// MARK: - External Extensions.
+
+public extension UserDef {
+  func render(fixWidth: CGFloat? = nil, extraOps: ((inout UserDefRenderableCocoa) -> Void)? = nil) -> NSView? {
+    var renderable = toCocoaRenderable()
+    extraOps?(&renderable)
+    return renderable.render(fixWidth: fixWidth)
+  }
+
+  func toCocoaRenderable() -> UserDefRenderableCocoa {
+    .init(def: self)
+  }
+}