Chrome/Brave extension: add per-tab vs all-tabs side panel visibility option

Summary

The ChatGPT/Codex browser side panel currently remains visible when switching to other tabs, including tabs where I never explicitly opened ChatGPT. In Brave (Chromium), each newly opened/switched-to tab can therefore have the side panel occupying page width with a new/separate chat window.

This is disruptive for workflows where ChatGPT is only needed alongside specific pages.

Proposed behavior

Add an extension preference for side-panel visibility with two modes:

1. All tabs in this window — current behavior; the panel remains visible while switching tabs.
2. Per tab / Only tabs where I open ChatGPT — the panel is visible only on tabs where the user explicitly opened it. Switching to a tab where it has not been opened hides the panel; returning to a tab where it was opened restores it.

Ideally, panel visibility should be independent from conversation identity/state. Choosing per-tab visibility should not necessarily imply that every tab must create a new conversation.

Expected per-tab workflow

• Open ChatGPT side panel on Tab A → panel appears on Tab A.
• Switch to Tab B, where ChatGPT was never opened → no side panel; webpage uses the full browser width.
• Explicitly open ChatGPT on Tab B → panel appears there.
• Return to Tab A → its panel remains/restores as appropriate.

Chromium API support

Chromium's Side Panel API supports tab-specific configuration via chrome.sidePanel.setOptions({ tabId, ... }) and tab-specific opening. Chrome's documentation describes tab-specific panels being hidden when switching to a tab where the panel is not enabled and appearing again when returning to an enabled tab.

Reference: https://developer.chrome.com/docs/extensions/reference/api/sidePanel

This suggests the extension could expose the behavior as a user-selectable option rather than forcing one visibility model.

Environment

• Browser: Brave (Chromium)
• Extension: official ChatGPT/Codex browser extension

This should ideally behave consistently across Chromium-based browsers supported by the extension.

Start with Chromium's Side Panel API, especially tab-specific setOptions behavior and tab-specific opening, and trace how the extension currently opens and persists panel state. Done means a selectable all-tabs or per-tab preference works across the described Tab A/Tab B workflow without unnecessarily coupling panel visibility to conversation identity.