What is the 'Neural Link'?

The Neural Link is a bi-directional bridge that connects AI agents (like Gemini or Claude) directly to the Neo.mjs runtime. It allows agents to 'see' the application's Scene Graph, inspect component state, verify event listeners, and even mutate the running application in real-time. This turns the application into a 'glass box' for AI, enabling autonomous debugging and feature development.

Why is Neo.mjs called an 'Application Engine' instead of a framework?

Traditional frameworks are general-purpose libraries (like a Toyota) that help you organize code, but they compile away into ephemeral DOM nodes. Neo.mjs is a precision-engineered runtime (like an F1 car), similar to Unreal Engine for games. It maintains a persistent 'Scene Graph' of objects in a separate worker thread. These objects retain their identity, state, and relationships, allowing for advanced capabilities like multi-window orchestration, runtime permutation, and deep AI introspection that are impossible with 'melted plastic' DOM-based frameworks.

What is 'Context Engineering'?

Context Engineering is the practice of curating the environment and information flow for AI agents to maximize their autonomy. In Neo.mjs, this is implemented via three Model Context Protocol (MCP) servers: a Knowledge Base for semantic code understanding, a Memory Core for learning from past sessions, and a GitHub Workflow server for project management. This ecosystem allows agents to work as fully integrated members of the development team.

What is 'Object Permanence' in the context of Neo.mjs?

In Neo.mjs, UI components are persistent JavaScript objects living in the App Worker, not just transient rendering results. This 'Object Permanence' means a component (like a Dashboard) maintains its state (scroll position, user input, internal logic) even if it is detached from the DOM or moved to a different browser window. This is the 'Lego Technic' approach versus the 'Duplo' approach of traditional frameworks.

What is an 'Agent Operating System'?

Neo.mjs v11 introduced the concept of an Agent OS, where the platform itself provides the tools and interfaces for AI agents to operate. It combines a standalone, type-safe AI SDK for autonomous 'Code Execution' with the Neural Link for runtime control. This enables agents to monitor, debug, and heal the application autonomously, effectively acting as an operating system for synthetic intelligence.

How does Neo.mjs handle multi-window applications?

Neo.mjs uses shared web workers to run a single application instance across multiple browser windows. All windows share the same application state and data in real-time. Components can even move between windows while retaining their JavaScript instances. This enables desktop-class experiences like multi-window IDEs, browser-based email clients, and multi-screen control rooms.

What makes Neo.mjs different from React, Angular, or Vue?

Neo.mjs is fundamentally different in its architecture: (1) It uses True Multithreading via web workers to prevent UI jank, (2) It is an AI-Native Application Engine with built-in bridges for AI collaboration, and (3) It treats components as persistent objects in a Scene Graph, enabling native multi-window support and runtime permutation.

Frontmatter

id	8121
title	Fix popup window sizing: race condition, caching, and rounding
state	Closed
labels	bugairefactoring
assignees	tobiu
createdAt	Dec 16, 2025, 2:39 PM
updatedAt	Dec 16, 2025, 3:35 PM
githubUrl	https://github.com/neomjs/neo/issues/8121
author	tobiu
commentsCount	1
parentIssue	null
subIssues	[]
subIssuesCompleted	0
subIssuesTotal	0
blockedBy	[]
blocking	[]
closedAt	Dec 16, 2025, 3:35 PM

Fix popup window sizing: race condition, caching, and rounding

Name: Neo.mjs Application Engine
Author: Neo.mjs

Closed v11.17.0 bugairefactoring

tobiu commented on Dec 16, 2025, 2:39 PM

We encountered and fixed multiple issues related to drag-and-drop popup window sizing and management.

1. Race Condition in DragProxyContainer Sizing

Problem: DragProxyContainer (used in SortZone) was created with layout: 'fit' but initially empty. Its DOM element would render with a default/minimal height (e.g., 155px) before the dragged content (e.g., 220px) was inserted.
Impact: The main thread DragDrop addon would sometimes capture this initial "empty" height during drag:move, causing dragBoundaryExit events to report incorrect proxyRect dimensions.
Fix: Updated src/draggable/DragZone.mjs to explicitly set config.height and config.width on the DragProxyContainer at creation time, matching the dragged element's dimensions.

2. Browser Window Dimension Caching

Problem: Re-opening a popup window with the same window.name caused browsers (like Chrome) to ignore the new windowFeatures (height/width) and instead reuse the cached dimensions from the previous session. This persisted the incorrect "155px" height even after the race condition was fixed.
Impact: Popup windows would open with the wrong size.
Fix: Refactored src/Main.mjs to use crypto.randomUUID() for the actual browser window target name. This ensures every windowOpen call creates a fresh window context, bypassing the cache. We also enhanced the internal openWindows map to store {win, targetName} to maintain correct logical references.

3. Fractional Window Dimensions

Problem: Calculated popup dimensions (e.g., 219.5px) were being passed to window.open.
Impact: Browsers expect integer values for windowFeatures. Passing floats can lead to parsing errors or unpredictable fallback behaviors.
Fix: Updated apps/agentos/view/StrategyPanelController.mjs to round all calculated dimensions (height, width, left, top) using Math.round() before passing them to windowOpen.

Changes:

src/draggable/DragZone.mjs: Explicitly set container proxy height.
src/Main.mjs: Implemented UUID-based window targeting and refactored openWindows map.
apps/agentos/view/StrategyPanelController.mjs: Added rounding to window feature calculations.

tobiu added the bug label on Dec 16, 2025, 2:39 PM

tobiu added the ai label on Dec 16, 2025, 2:39 PM

tobiu added the refactoring label on Dec 16, 2025, 2:39 PM

tobiu assigned to @tobiu on Dec 16, 2025, 2:39 PM

tobiu referenced in commit 647c5c9 - "Fix popup window sizing: race condition, caching, and rounding #8121" on Dec 16, 2025, 2:40 PM

tobiu referenced in commit f91e513 - "#8121 enforcing a "fixed" popup size" on Dec 16, 2025, 3:30 PM

tobiu Dec 16, 2025, 3:33 PM

Input from Gemini:

✦ ### Final Resolution & Insights

We encountered a persistent issue where popup windows would resize unpredictably (e.g., jumping from 156px to 219px, or getting stuck at 156px) even up to 300ms after opening. This was caused by the browser attempting to adapt the window size to the content:

The Problem: When requesting a window with height=219, the browser interprets this as the inner height (viewport). However, due to browser chrome (headers/toolbars), the effective outer height becomes larger (e.g., ~282px). If the dragged content (219px) was then inserted into a window where the inner height was reduced by chrome (e.g., 156px), the browser would sometimes auto-expand the window to fit the content, causing layout shifts.

The Fix ("Give Size"): We implemented a strategy to immediately call openedWindow.resizeTo(openedWindow.outerWidth, openedWindow.innerHeight) upon creation. This effectively forces the window's outer height to match the current inner height.

This locks the dimensions, ensuring the popup's total footprint exactly matches the drag proxy.

It prevents the browser from auto-resizing based on content insertion later in the lifecycle.

New Feature: useTotalHeight We added an optional useTotalHeight config to Neo.Main.windowOpen (defaults to true).

Concept: This acts similarly to box-sizing: border-box in CSS.

Behavior: It ensures the requested height is treated as the total outer height of the window, ignoring the size of browser header tools. This guarantees that a 219px drag proxy results in exactly a 219px popup window, preserving the visual continuity of the drag operation.

tobiu closed this issue on Dec 16, 2025, 3:35 PM