GHS Markdown Editor — Cross-Platform

A feature-rich Markdown editor for Windows and macOS, built with Avalonia UI. Part of the GHS Markdown Editor ecosystem.

What's New in v1.1.2

• Multi-file tabs — open multiple documents simultaneously in a tab strip built into the titlebar
• Tab persistence — open tabs are restored on relaunch with the same active tab and scroll positions
• Single-instance enforcement — opening a file from Explorer when the app is already running opens it in a new tab rather than launching a second window
• Custom theme syntax colors — H1–H6, Bold, Italic, Code, and Blockquote colors are individually configurable in GHS Custom theme
• Draggable right panel — resize the right panel by dragging its left edge
• Anchor-based scroll sync — scroll sync stays aligned on long and complex documents without drift
• Click-to-sync in tables — clicking table content in the preview now correctly syncs the editor cursor

Features

Editor

• Live split-pane editor and preview with anchor-based synchronized scrolling
• Multi-file tab editing — tab strip in titlebar, Ctrl+T / Ctrl+W / Ctrl+Tab
• Syntax highlighting for headings, bold, italic, code, links, blockquotes, and lists
• Right-click context menu with formatting, clipboard, and persistent toggle options
• Formatting toolbar with bold, italic, strikethrough, headings, lists, tables, links, and images
• Code block language picker — 28 languages, searchable
• Word wrap, line numbers, and current line highlight (persisted between sessions)
• Drag-and-drop file open

Preview

• Live Markdown preview with GHS-styled CSS
• Inline editing — double-click any paragraph, heading, list item, blockquote, code block, or table to edit source directly
• Click any preview element to sync the editor cursor (including tables)
• Detached preview window for dual-monitor workflows

Themes

• GHS Dark (default), GHS Light, and GHS Custom
• Custom theme editor with 10 UI chrome color tokens + 10 Markdown syntax color tokens
• Reset custom theme to Dark or Light baseline
• Auto mode follows OS appearance

Tools

• AI Assist panel powered by the Anthropic API (streaming)
• Document Topology and Outline panels (per-tab)
• Snippet Studio with tab-stop insertion
• Version Timeline with auto-snapshot and manual restore
• Command Palette (Ctrl+P)
• Git diff margin — green, amber, and red line indicators vs last commit
• Focus Mode with prose dimming
• Draft auto-save and crash recovery

Export & Print

• Export to PDF, Word (.docx), HTML (styled and clean), and plain text
• Print via system print dialog (Ctrl+Shift+P)

Platform

• Single-instance enforcement with named pipe IPC (Windows)
• Windows Jump List integration
• Tab state persisted across restarts (up to 10 tabs restored)
• Unsaved-changes dialog on tab close and app exit

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GHS Markdown Ecosystem

App	Platform	Repo	Live
GHS Markdown Web	Browser	MarkDown-React-Firebase	md.theheadfamily.com
GHS Markdown for Windows	Windows (WPF)	MarkDown-WindowsApp	—
GHS Markdown Cross-Platform	Windows + macOS	MarkDown-CrossPlatform	This repo

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Keyboard Shortcuts

Action	Shortcut
New File	Ctrl+N
Open File	Ctrl+O
Save	Ctrl+S
Save As	Ctrl+Shift+S
Print	Ctrl+Shift+P
New Tab	Ctrl+T
Close Tab	Ctrl+W
Next Tab	Ctrl+Tab
Command Palette	Ctrl+P
Edit Only	Ctrl+Shift+E
Split View	Ctrl+Shift+T
Preview Only	Ctrl+Shift+W
Focus Mode	Ctrl+Shift+F
Detach Preview	Ctrl+D
Toggle Formatting Toolbar	Ctrl+Shift+B
Bold	Ctrl+B
Italic	Ctrl+I
Inline Code	Ctrl+`
Insert Link	Ctrl+K
Heading 1–6	Ctrl+1–6
Strikethrough	Ctrl+Shift+X
Unordered List	Ctrl+Shift+U
Ordered List	Ctrl+Shift+O
Insert Table	Ctrl+Shift+G
Insert Image	Ctrl+Shift+I
Horizontal Rule	Ctrl+Shift+H

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Tech Stack

• C# / .NET 10
• Avalonia UI 12.0.0
• AvaloniaEdit 12.0.0
• Markdig 0.44.0
• FluentAvaloniaUI 2.5.1
• DocumentFormat.OpenXml 3.5.1
• WebView2 (Windows) / WKWebView (macOS)

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Installation

Windows

Download GHSMarkdownEditor-Setup-1.1.0.exe from the latest release and run the installer.

macOS

Download GHSMarkdownEditor-1.1.0.dmg from the latest release, open it, and drag the app to Applications.

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Building from Source

Requirements: .NET 10 SDK, Visual Studio 2022 17.13+ or JetBrains Rider.

git clone https://github.com/michaeldhead/MarkDown-CrossPlatform.git
cd MarkDown-CrossPlatform
dotnet build GhsMarkdown.Cross/src/GhsMarkdown.Cross/GhsMarkdown.Cross.csproj
dotnet run --project GhsMarkdown.Cross/src/GhsMarkdown.Cross/GhsMarkdown.Cross.csproj

Windows publish (self-contained)

dotnet publish GhsMarkdown.Cross/src/GhsMarkdown.Cross/GhsMarkdown.Cross.csproj \
  -r win-x64 -c Release --self-contained

macOS publish (self-contained)

dotnet publish GhsMarkdown.Cross/src/GhsMarkdown.Cross/GhsMarkdown.Cross.csproj \
  -r osx-arm64 -c Release --self-contained

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License

MIT