From 16296a27da4b3315e0ad872a5268cc6d950e83dd Mon Sep 17 00:00:00 2001
From: Jonathan van Rij <jonathan@blijnder.nl>
Date: Tue, 16 Jun 2026 13:35:28 +0200
Subject: [PATCH] multiple instances

---
 src/main/index.ts | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/src/main/index.ts b/src/main/index.ts
index 1c6ce04..645f976 100644
--- a/src/main/index.ts
+++ b/src/main/index.ts
@@ -1,5 +1,6 @@
 import { join, resolve, sep } from 'node:path'
 import { readFileSync, statSync } from 'node:fs'
+import { spawn } from 'node:child_process'
 import { app, dialog, shell, BrowserWindow, ipcMain, Menu } from 'electron'
 import { watch, type FSWatcher } from 'chokidar'
 import { addRecentProject, getName, getRecentProjects, getRoot, openDialog, setRoot } from './project'
@@ -27,6 +28,32 @@ function broadcast(channel: string): void {
   for (const w of BrowserWindow.getAllWindows()) w.webContents.send(channel)
 }
 
+/**
+ * Each Helder window is one project, and one project owns global main-process
+ * state (root + FS/git/config watchers + PTYs). To run several projects beside
+ * each other we therefore spawn a *separate, detached* Helder process per window
+ * rather than opening a second BrowserWindow in this process.
+ *
+ * Spawning `process.execPath` directly also sidesteps macOS LaunchServices, which
+ * otherwise just re-activates the running instance when the bundle is launched
+ * again from Finder/Dock. `HELDER_PROJECT` points the child at a project (the
+ * child's `resolveInitialRoot` reads it); with no path it lands on the launcher.
+ */
+function spawnInstance(projectPath?: string): void {
+  const env = { ...process.env }
+  if (projectPath && safeIsDir(projectPath)) env.HELDER_PROJECT = resolve(projectPath)
+  else delete env.HELDER_PROJECT
+  // Packaged: execPath IS the app, no app path needed. Dev: replay our own argv
+  // (the electron-vite main entry) so the child loads the same app.
+  const args = app.isPackaged ? [] : process.argv.slice(1)
+  const child = spawn(process.execPath, args, { detached: true, stdio: 'ignore', env })
+  child.unref()
+}
+
+function safeIsDir(p: string): boolean {
+  try { return statSync(p).isDirectory() } catch { return false }
+}
+
 function startConfigWatcher(): void {
   if (configWatcher) { configWatcher.close(); configWatcher = null }
   const root = getRoot()
@@ -96,6 +123,11 @@ function buildAppMenu(): Menu {
     {
       label: 'File',
       submenu: [
+        {
+          label: 'New Window',
+          accelerator: 'CmdOrCtrl+Shift+N',
+          click: () => spawnInstance(),
+        },
         {
           label: 'Open Folder…',
           accelerator: 'CmdOrCtrl+O',