Steps to reproduce

• Open Firefox in a new profile
• Install Sidebery nightly from this repo (the issue started a few weeks ago)

Actual behavior

Opening a new tab via middle-click, Ctrl+click, or the "Open Link in New Tab" context menu opens a sibling tab instead of a child tab. Unfortunately, the console logs don’t show anything while this happens.

Expected behavior

A new nested child tab should have been created instead of a sibling tab. Installing the stable build from AMO restores the expected behavior.

System

Windows 10, macOS 15.7.1

Firefox version

144.0.2

Sidebery version

5.3.3.32

Logs