Cursor 2.7.0’s Glass layout killed the secondary sidebar — and with it, the ability to pin Codex or Claude extensions as tabs next to Cursor’s own chat panel on the right.
The change shipped as part of the new Glass UI system, which replaces VS Code’s auxiliary bar with its own panel architecture. Cursor forum staff confirmed it’s a “known limitation,” not a bug.
What changed in 2.7.0:
- Right sidebar is Cursor-only — Glass claims the entire auxiliary bar for Cursor’s chat and agent panels
- Extensions moved to left sidebar — Codex, Claude, and other extensions must run from the Activity Bar on the left
- No drag-to-right workaround — users who previously dragged extension tabs to the secondary bar report no option to do so
- Functionality preserved — extensions still work, just repositioned
Users who ran the “triple C” setup — Cursor, Codex, and Claude stacked on the right, switched with a click — lost that workflow overnight. One Reddit user framed it as Cursor claiming the right side as its exclusive territory, questioning the IDE’s value when cheaper models are catching up to Composer 2.5.
NOTE
Cursor staff indicated a fix may come but gave no timeline. The forum thread remains open.
The workaround for now: keep extensions on the left Activity Bar and use keyboard shortcuts to toggle sidebars, or run Claude Code in a split terminal pane alongside Cursor for a multi-agent setup.