Background flicker when focusing inactive tab after OS theme change

[MrConnorKenway]

Issue Description

The active tab's background changes immediately as system theme changes, while background color of inactive tabs are not, resulting in a sudden color change when focusing them.

Reproduction Steps

1. Open ghostty and create a few tabs
2. Switch OS theme
3. Focus inactive tab

ghostty.mov

As shown in the video, there is a black flicker when switching to inactive tab:

Ghostty Version

Ghostty 1.1.3

Version
  - version: 1.1.3
  - channel: stable
Build Config
  - Zig version: 0.13.0
  - build mode : builtin.OptimizeMode.ReleaseFast
  - app runtime: apprt.Runtime.none
  - font engine: font.main.Backend.coretext
  - renderer   : renderer.Metal
  - libxev     : main.Backend.kqueue

OS Version Information

macOS 15.1.1

(Linux only) Display Server

None

(Linux only) Desktop Environment/Window Manager

No response

Ghostty Configuration

theme = light:catppuccin-latte,dark:catppuccin-mocha

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.