macOS: split handle drags window, not split, when macos-titlebar-style = hidden

[danielwe]

Issue Description

With macos-titlebar-style = hidden, a split drag handle that lies along the top of the window will drag the window instead of the split.

Expected Behavior

The split handle always drags the split. (A similar mechanism for dragging windows without a titlebar could be useful, but it must be separate.)

Actual Behavior

The window is dragged and the split layout is unaffected. Edge case: if the window dragged such that it triggers the OS's automatic tiling, the split you tried to drag may pop out into its own window.

Screen.Recording.2025-12-29.at.14.02.53.mov

Reproduction Steps

1. Open Ghostty
2. Create a vertical split (Cmd+D)
3. Try dragging a handle to rearrange the splits.

Ghostty Logs

[Nothing is logged during this]

Ghostty Version

Ghostty 1.3.0-main+b9ad1f05e

Version
  - version: 1.3.0-main+b9ad1f05e
  - channel: tip
Build Config
  - Zig version   : 0.15.2
  - build mode    : .ReleaseFast
  - app runtime   : .none
  - font engine   : .coretext
  - renderer      : renderer.generic.Renderer(renderer.Metal)
  - libxev        : kqueue

OS Version Information

macOS 26.2 (Tahoe)

(Linux only) Display Server

None

(Linux only) Desktop Environment/Window Manager

No response

Minimal Ghostty Configuration

macos-titlebar-style = hidden

Additional Relevant Configuration

No response

I acknowledge that:

• I have reviewed the FAQ and confirm that my issue is NOT among them.
• I have searched the Ghostty repository (both open and closed Discussions and Issues) and confirm this is not a duplicate of an existing issue or discussion.
• I have checked the "Preview" tab on all text fields to ensure that everything looks right, and have wrapped all configuration and code in code blocks with a group of three backticks (```) on separate lines.