KryptonMenuBar

Overview

KryptonMenuBar is a native (non-ToolStrip) horizontal menu bar in Krypton.Toolkit. It is the follow-up to KryptonMenuStrip requested in #4242.

Problem: KryptonMenuStrip still paints through ToolStripManager, so fonts, colours, and item types cannot fully match KryptonContextMenu.
Scope: Top-level KryptonContextMenuItem / KryptonContextMenuSeparator laid out horizontally; click, Alt, and mnemonic open nested item.Items as a KryptonContextMenu popup.
Not in v1: MDI merging, ToolStripItem hosts, floatable panels (KryptonFloatableMenuStrip stays on KryptonMenuStrip).

KryptonMenuStrip remains the WinForms MenuStrip equivalent (Toolbox designer Insert Standard Items for ToolStrip items, MainMenuStrip, MDI merge). To show that strip in the caption, assign it to KryptonFormTitleBar.MenuStrip (see Documents/Development/KryptonMenuStrip.md); that is not KryptonMenuBar.

Architecture

KryptonForm.MenuBar  (assignment only; ProcessCmdKey)
        |
KryptonMenuBar : VisualSimpleBase
  ViewDrawDocker          (MenuStrip ColorTable background; ColorAlign Local)
    ViewLayoutStack       (horizontal)
      ViewDrawMenuBarItem + MenuBarItemController
      ViewDrawMenuBarSeparator
        |
        click / hover-switch / mnemonic
        |
  KryptonContextMenu.ShowCollection(item.Items)
    VisualContextMenu popup

Key types:

Type	Role
`KryptonMenuBar`	Host control (`VisualSimpleBase`, `Dock = Top` by default)
`KryptonMenuBarItemCollection`	Restricted to `KryptonContextMenuItem` and `KryptonContextMenuSeparator`
`ViewDrawMenuBarItem`	Low-profile button view for a top-level item
`ViewDrawMenuBarSeparator`	Vertical separator
`MenuBarItemController`	`ClickOnDown` + `BecomesFixed`; hover-switch while open
`KryptonStandardMenuFactory`	Shared File / Edit / Tools / Help trees (also used by `KryptonFormTitleBar`)
`KryptonContextMenu.ShowCollection`	Internal: show an existing `KryptonContextMenuCollection` by reference

Drop-downs do not move designer-owned nodes onto a temporary menu. ShowCollection passes item.Items into VisualContextMenu the same way submenus do.

Public API

`KryptonMenuBar`

Items — KryptonMenuBarItemCollection (DesignerSerializationVisibility.Content)
UseMnemonic — default true
InsertStandardItems() — File, Edit, Tools, Help via KryptonStandardMenuFactory.CreateStandardMenuBarItems()
Palette: inherited PaletteMode / LocalCustomPalette; StateCommon / StateDisabled / StateNormal / StateTracking / StatePressed (item chrome, ButtonLowProfile); StateBarBackground (MenuStrip ColorTable inherit; ColorAlign / ImageAlign must be Local for RenderStandard.DrawBack)
Toolbox: [ToolboxItem(true)], ToolboxBitmaps.KryptonMenuBar.bmp

`KryptonForm.MenuBar`

Assignment-only ([DefaultValue(null)]). Does not dock or reparent. Coexists with MainMenuStrip.

KryptonForm.ProcessCmdKey calls KryptonMenuBar.ProcessBarCmdKey first so shortcuts (Items.ProcessShortcut) and Alt/F10 menu-mode work while the bar is non-selectable.

Mnemonics (ProcessMnemonic) work whenever the bar is a child of the form, even without MenuBar assignment.

Designer

Collection editor: only Item + Separator at the top level; nested item.Items keep the full context-menu editor
Designer verb / action list: Insert Standard Items
Default drop: Dock = Top

Usage

var bar = new KryptonMenuBar();
bar.InsertStandardItems();
form.Controls.Add(bar);
form.MenuBar = bar; // shortcuts + Alt activation

foreach (KryptonContextMenuItemBase item in bar.Items)
{
    if (item is KryptonContextMenuItem file && file.Text.Contains("File"))
    {
        // Nested drop-down is file.Items (usually one KryptonContextMenuItems group)
    }
}

Wire KryptonContextMenuItem.Click or KryptonCommand on nested items. Top-level items with an empty Items collection fire PerformClick() instead of opening a popup.

Keyboard

Input	Behaviour
Alt / F10	Toggle menu mode (first item highlighted) when assigned to `KryptonForm.MenuBar`
Alt+letter	`ProcessMnemonic` opens the matching top-level drop-down
Left / Right	Menu mode: move highlight. Root popup (stack depth 1): switch adjacent top-level item
Down / Enter / Space	Open highlighted item
Escape	Close root popup and keep menu mode, or leave menu mode
Shortcuts	`Items.ProcessShortcut` from `KryptonForm.ProcessCmdKey`

Nested submenus keep existing context-menu Left-dismiss / Right-open behaviour when popup stack depth is greater than 1.

Edge cases

Ownership: Never add the same KryptonContextMenuItem instance to both a bar and a standalone KryptonContextMenu.Items collection; collections assume exclusive parentage.
C# / TFM: New files stay within the Toolkit LangVersion and net472 surface.
Coexistence: Setting both MenuBar and MainMenuStrip is allowed; shortcuts on the native bar are processed first.
Hover-switch: While a drop-down is showing, moving the mouse to another top-level item closes the current popup and opens the new one (BecomesFixed is cleared on Closed).

Validation

TestForm: KryptonMenuBarDemo (StartScreen: “KryptonMenuBar (#4242)”). Side-by-side KryptonMenuBar / KryptonMenuStrip / MenuStrip; Insert Standard Items; theme combo; Ctrl+N; Alt/mnemonic; hover-switch.
Demos: KryptonMenuBar Examples on branch alpha-4242-krypton-menu-bar in Standard-Toolkit-Demos.