+1 this is severely irritating because I can’t trust whether the extension will work on any given update. For the past few months its been going back and forth between usable and unusable but if this is the only solution I’m unironically cancelling my ultra subscription.
Hi, thanks for your post! Short answer: this is intentional. The Secondary Side Bar, the right hand panel where your Cursor Agent tabs live, is reserved for Cursor’s own agent UI, so extensions can’t register a view container there. The Agent tab group itself only accepts Cursor chat tabs, which is why dragging Codex over it gives you no drop target, and why View: Move Editor into Right Group doesn’t reach it. That panel isn’t a regular editor group, so there’s nothing for the command to target.
Your “this worked immediately before upgrading” is correct, and I want to be transparent with you. For roughly a month, a change on our side made that docking possible again when it wasn’t meant to be, and 3.15.6 brings it back in line. So the layout you had really did exist, and it wasn’t anything you configured. There’s no setting that restores it.
What you can do now:
Codex should live in the left sidebar. If it lands nested inside Explorer, drag its section header onto the Activity Bar so it gets its own top level icon. That’s much closer to how it used to feel. Running View: Reset View Locations followed by Developer: Reload Window first can help if it’s stuck. Fair warning, the drag can take a few tries to stick.
For a genuine side by side setup, open Codex with Codex: New Codex Agent from the Command Palette, then run View: Split Editor Right or drag the tab to the right edge of the editor area. It’ll sit beside your code as its own editor group instead of inside the Agents panel.
If you had a keybinding on Focus on Codex View and it stopped responding, rebinding it to Codex: Open Codex Sidebar gets the shortcut working again.
One to avoid: don’t manually move the Codex view into the Secondary Side Bar. It renders blank rather than falling back cleanly, so you’ll end up worse off than the left sidebar.
Just a heads up, I’ve validated that the above Cursor commands are correct - View: Reset View Locations and Developer: reload window. But I do not have the Codex extension installed personally, so I have not validated those steps before this post. If you have any follow-up questions, let me know!
Thanks for the clarification. I appreciate the transparency that this is an intentional change and not a bug.
That said, I think this is a significant regression in the user experience.
Having Codex in the Secondary Side Bar alongside the Cursor Agent tabs was by far the most productive layout I’ve used. It allowed me to switch instantly between Cursor Agent conversations and Codex without consuming additional editor space or forcing me to move my attention across different parts of the UI.
Restricting the Secondary Side Bar to Cursor’s own agent UI feels unnecessarily limiting. As a user, I don’t really care whether a tab is implemented as a “Cursor Agent” or an “extension”—I care about having related AI tools in one place.
The suggested alternatives are not equivalent:
Keeping Codex in the left sidebar separates it from the rest of my AI workflow.
Opening Codex as a separate editor group consumes valuable editor space and is much less convenient than simply switching tabs.
Keeping Codex in the left sidebar has also created a layout nightmare. That sidebar is where I keep my project folder tree. Every time I open Codex, it blocks the Explorer and I lose visibility into my project structure. I constantly have to switch back and forth between the Explorer and Codex just to navigate files and continue coding. Before 3.15.6, I could keep the project tree visible on the left while having all of my AI conversations—including Codex—in the Secondary Side Bar on the right. That workflow was significantly more efficient.
The previous behavior made Cursor feel like a unified AI workspace. The new behavior makes it feel fragmented.
I would strongly encourage the team to reconsider this restriction, or at least make it a user-configurable option. If the Secondary Side Bar is technically capable of hosting Codex (as it clearly was for many users), there should be a way to opt into that layout.
This change has noticeably reduced the usability of Cursor for my workflow, and I hope the team will reconsider it.
I’m on v3.15.6 Win11 (I have no mac to test it on)
Codex extension is missing but the second error/warning had led me to find it at the bottom of the explorer.
Press and Hold then drag it to the left primary side bar.
You can then right click on it to move to right secondary side bar in the agent tab group as before (Cursor may remove this ability soon)
Whoever is making these decisions at Cursor is doing a terrible job.
Codex and Claude Code used to share the same sidebar, which kept everything tidy and made it easy to switch between providers and Cursor Composer. Seriously, what was wrong with that?
Every time they push an update, it breaks something else. I understand there’s no obligation to ensure third-party extension works perfectly, but given that Cursor is a VS Code fork, and many of us use it because we’ve gotten used to the IDE over the past year, users deserve a bit more respect than this.
I downgraded to 3.14.27 just because of this, and I won’t be upgrading again anytime soon and I suggest everyone to do the same.
I don’t know your exact current situation. These are the only steps I took. This only barely moves Codex to the right side, and it cannot coexist with Cursor’s auxiliary panel.If you want to use them at the same time, someone above has replied, you can ask him. But he also said (Cursor may remove this ability soon)
Thank you for taking the time to share these screenshots.
I really hope Cursor brings back the ability to keep Codex and Claude in the Secondary Side Bar alongside the Cursor Agent tabs. That was by far the cleanest and most productive layout for me.
The new setup takes up significantly more screen space and adds unnecessary friction, especially when repeatedly switching between tabs and panels. Having all the AI tools together in the Secondary Side Bar made the workflow much more seamless and efficient.
Hi @clear-moon For me, after following the first three steps, I still cannot drag the Codex Agent window from the central editor area to the right side. Do you have any advice on how to resolve this issue?
Hello there. Any news about this ? It’s annoying. I understand that it could happens once. But it’s at least the second time it happens, and it takes days to be fixed..
And having Codex on the right, where I already have Cursor agents, is not a good workaround, unfortunately.
This is a major regression, and for me it’s the nail in the coffin.
After 3.15.6, Claude Code, Cline, and Roo Code are effectively gone from the right Agents/chat panel where I actually worked. Claude Code now opens as an editor tab instead of the extension chat UI. Same breakage pattern for Cline and Roo.
Staff confirmed this is intentional: the secondary sidebar / Agents panel is reserved for Cursor’s own agent UI, and third-party extensions can’t live there anymore. For about a month docking worked again; 3.15.6 closed that hole.
That right-side multi-agent layout was not a niche preference. It was the core reason Cursor was strong for me:
files on the left
Cursor Agent + Claude Code + Cline + Roo as tabs on the right
switch tools without burning editor space or burying them under Explorer
The “workarounds” are not equivalent. Left Activity Bar / nested under Explorer fights the file tree. Editor tabs / splits burn coding space. None of that restores the unified AI workspace we had.
I’m past the “thinking about canceling” stage. I previously had two Pro accounts. I already downgraded both to standard $20 accounts because the product had become unusable for my workflow. This change is forcing me the rest of the way — I’m canceling altogether.
This is part of a broader pattern:
Constant updates keep rewriting the environment and removing control over how we work
We can’t manage our own layout / tooling the way we could before
Cursor keeps installing skills that compete with ours, and we can’t delete them
The product I originally purchased — an open, extensible VS Code fork where third-party agents were first-class — has been progressively hijacked into a locked, single-vendor Agents UI
I don’t care whether a tab is implemented as “Cursor Agent” or “extension.” I care about controlling my own environment and running multiple AI tools side by side. Locking the right panel to Cursor-only tools is an anti-user move, and it breaks the trust that made people build workflows on this IDE.
Please restore:
third-party AI extension docking in the secondary sidebar / Agents tab group, OR
a clear setting: “Allow third-party AI extensions in Agents/secondary sidebar”
And separately: give users real control to remove/disable Cursor-installed skills that compete with our own.
If this direction stands, Cursor is no longer the tool I paid for — and I’m done paying for it.
Yes! True strength is not achieved by suppressing competitors! True strength is achieved through one’s own abilities!
I am a developer, I don’t care. I will use whoever is better! But I still hope that the cursor team can consider the needs of developers and not restrict their use!
My thing is the adaptability, There are 100% days where all I use is Cursor but that is because Claude Code and or Codex are having a fit.
Then there are days where im the opposite.
I have four screens and two machines, two Cursor plans, two Claude plans, Two Codex plans.
With model routing being so un predictable I use which ever session decides it wants to work that day.
Locking out my choices and my overall flow just puts me in a box. That means if my agent window is deciding to have a fit that day, then im not able to continue my workflow the same.
It doesn’t help that for five weeks now Cursor has been shipping updates and changes faster than I can adjust my environment for. I have spent over 20 hours a week just managing SKILL and Hook files.
I spent 7 hours yesterday alone going back through them all to make sure I was adjusted for the all the model changes and to wake up to now my entire IDE flow being altered.
I cannot begin to explain the sheer insanity I feel right now. Absolute madness. My IDE is not where I just code. Its where i literally make my living. I am a small business owner, I deliver client work through the use of Cursor IDE, im not just in here doing one off projects with no real use. Im actively delivering work that puts food on the table for my family.
So to have to constantly be re managing my entire day to day with no stability and now lack of options feels like someone just punched me in the gut.
I understand how you feel, and I am in the same situation as you. I am a full-time full stack developer!
To be honest, I really dislike using CLI agents (including codex, Claude Code!)! But this does not include VSCode extensions for codex and claude code, because even for Vibe coding, I don’t like using CLI agents! That’s completely a black box! I prefer using IDEs because they can provide a better development experience! I now use IDEs more to modify project configuration files, so I never consider non AI IDEs. CLI agents can only be used by novice programmers!
So I did deceive everyone, cursor is really important to me!
But if it continues like this, it won’t work! We need more choices! We need more freedom! We need more control!
Devin, what do you think? Can we migrate to Devin?
