Moving tabs across windows copies them instead

[sig-kill]

Steps to reproduce

• Open Firefox in a new profile
• Install Sidebery
• Open a new window (shown left)
  • 
• Drag a tab from one Sidebery panel to the other

Actual behavior

Tab is copied over to the new window, and not active:

Expected behavior

Tab should be moved from the old window and made active in the new window. Result in the example should be this:

Moving tabs used to behave this way seamlessly (even moving a playing Youtube tab across windows worked without interrupting the video) so it seems like there's a regression.

System

Windows 10

Firefox version

129.0b5

Sidebery version

5.2.0

Logs

No console logs

[ForsakenHarmony]

Wonder if this is the same issue as #1714

[geduardcatalindev]

I have the exact same problem using the same versions of Firefox and Sidebery mentioned by @sig-kill

[Bobo1239]

Did some debugging like in #1714 (comment) and the regression is caused by the same Firefox change. Opened https://bugzilla.mozilla.org/show_bug.cgi?id=1912340 upstream since it's a different bug than what causes #1714 which already has a patch pending.

[Bobo1239]

The just released Firefox Nightly contains the fix and afaict everything works again. 🎉 All credits go to David Parks (handyman) who wrote the patches. Currently it is slated to land in Firefox 131 (scheduled for Oct. 1) but they may deem this important/unrisky enough to uplift to an earlier release.

Update: Got uplifted to beta (starting 130.0rc1) and should land on stable on September 3.

[sig-kill]

That's great news. Thanks for following up!

[sig-kill]

Confirmed working on 131.0b3