# Objective

As part of the transparent-window artifact fixes in #58981, multibuffer
header backgrounds stopped rendering whenever the window was transparent
or blurred.

This caused a regression for transparent themes, which commonly use an
opaque multibuffer header background to prevent editor text from showing
through sticky headers.


## Solution

Render `editor_subheader_background` when either the window or the
configured background color is opaque.

This restores opaque multibuffer header backgrounds as a mask for the
editor content beneath them, while preserving the #58981 behavior for
translucent backgrounds that would otherwise create a darker layered
region.

## Testing

Manually verified locally with a transparent theme that an opaque
multibuffer header background is rendered and prevents editor text from
showing through sticky headers.

## Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content adheres to Zed's UI standards
([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
and
[icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md)
guidelines)
- [ ] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

## Showcase

**Nightfox - opaque / blurred**

Before:

<img width="2566" height="1771" alt="图片"
src="https://github.com/user-attachments/assets/55b333bc-b029-4079-9bbc-86462a3f41a7"
/>


After:

<img width="2444" height="1687" alt="图片"
src="https://github.com/user-attachments/assets/217e1ee7-717c-4961-8db0-5eac8104e5bb"
/>

---

Release Notes:

- Fixed editor text showing through multibuffer headers and overlapping
header text in transparent themes.