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1. Background

In the v1.18 series update of the OpenCode desktop app, the original left-hand project/session sidebar was removed, and top tabs became the sole entry point for session management. The official design rationale states that “Tabs are better suited to AI coding multi-task workflows.” However, in actual use, the top-tabs mode causes three core problems in multi-project, multi-session workflows: loss of information hierarchy, elimination of at-a-glance overview, and increased operational cost. These issues seriously undermine the productivity of users who rely on OpenCode as their primary working environment.

This is not an aesthetic complaint that “the new UI looks bad.” It is a request concerning whether a professional tool still supports professional workflows.

2. Core Convenience of Having a Sidebar (the Value of the Old Layout)

2.1 The Sidebar Is a “Command Center,” Not Merely a Navigation Bar

The old left sidebar carried both the project list and the session list under each project, forming a clear two-level structure:

• Level 1: Projects. Multiple projects were visible side by side in the sidebar, so users could see at a glance which projects were open.
• Level 2: Sessions. Users could see which active sessions existed under each project, whether an agent was running, and which task was waiting or completed—all within the same field of view.

One long-term user described the old sidebar as a “command center”: it allowed them to see multiple projects at once, with all sessions under all projects visible at a glance, without having to infer from names or memory “which project this tab belongs to and what that session is doing.”

2.2 The Sidebar Preserved the Critical “Project → Session” Hierarchy

Real AI coding workflows naturally have two or even three levels: project → task/session → specific interaction. The old sidebar mapped this hierarchy directly through visual structure: a project is a container, and sessions are execution units within that container. Users did not need to maintain in their heads “which tab corresponds to which project,” because the sidebar already presented the answer.

2.3 The Sidebar Supported “Glanceable Monitoring” Rather Than “Clicking Through One by One”

In scenarios involving multiple parallel agents or long-running tasks, the user’s core action is not “frequent switching” but continuous monitoring: which session is stuck, which agent has finished, and which project has had no activity today. The vertical list in the sidebar made this monitoring possible through peripheral vision, without leaving the content currently being read or edited. This low-interruption global awareness is something top tabs structurally cannot provide.

3. Inconvenience of Not Having a Sidebar (Top Tabs Only)

3.1 The Project/Session Hierarchy Is Flattened, and Multi-Project Workflows Break Down

Top tabs flatten all sessions into a single row, and project ownership disappears from the UI. Users can only infer which project a session belongs to from the tab name, but tab widths are inherently limited; once the name is truncated, the ownership information is completely lost. In scenarios with more than 20 parallel sessions, this flattening directly creates a “multi-project blind spot”: users cannot see at all what is happening in other projects and must click through tabs one by one to confirm.

3.2 Information Density Drops Sharply, and Large-Screen Space Is Wasted

The old layout used horizontal space efficiently through the left sidebar. In the new layout, the left side is cleared, the session area is centered and width-constrained, and a large area on the left side of the screen sits idle. The space that should have been used to display projects, sessions, and agent status is completely vacant. For users working on large screens with multiple tasks, this means a net loss in information-access efficiency, not a gain from the interface “looking cleaner.”

3.3 Top Tabs Create Visual Clutter and Cognitive Overload with Many Sessions

The horizontal space for top tabs is linear and limited. Once more than 5–8 sessions are open at the same time, tabs are compressed and truncated, forming a dense row of text fragments that are both hard to locate quickly and incapable of carrying any status information. Community feedback explicitly states that putting 20+ sessions into top tabs “makes it extremely difficult to track, read, and manage” and causes “massive visual clutter.” The inherent limitation of horizontal tabs is this: they suit a small number of short-lived switching targets, not a large number of continuously existing monitoring targets.

3.4 Even When the Sidebar Exists as a “Floating Layer,” the Experience Is Far Worse Than a Fixed Column

In some versions, although the sidebar was retained, it was changed into a floating overlay that covers the chat content when opened and is accidentally triggered by hover-peek when the mouse moves, causing flickering and mis-navigation. This further demonstrates that the value of the sidebar lies precisely in its being a fixed structural column that does not compete for focus, not a temporary panel that must be “summoned.”

4. Typical Affected Workflows (Evidence)

The following scenarios come from public community feedback, all pointing to the damage that top-tabs mode does to professional workflows:

Scenario 1: A developer working on multiple projects in parallel. They maintain multiple projects simultaneously, and under each project there are multiple sessions for planning, implementation, refactoring, documentation, and so on. Top tabs make “which active sessions remain under a given project” invisible, significantly increasing cognitive cost.

Scenario 2: An “AI agent orchestrator” with 20+ parallel sessions. The user treats each persistent session as an “AI Employee” and needs to monitor and schedule more than 20 agents simultaneously from the sidebar. Top tabs make this orchestration approach visually infeasible and have been described as “a massive regression in usability and speed.”

Scenario 3: Relying on the sidebar to judge agent activity status. Some users report that after losing the sidebar, they “no longer have easy visibility over which one of my projects has active agent activity” and can only infer it from session titles, which are often inaccurate.

These are not edge cases. OpenCode’s core user group consists precisely of developers who treat AI coding tools as their primary working environment and operate multiple projects and agents simultaneously. Top-tabs mode may be usable in “lightweight, single-project, few-session” scenarios, but sacrificing the core workflows of professional users in exchange for a “cleaner look” is the wrong direction.

5. Explicit Requests

5.1 Primary Request: Restore the Persistent Left Sidebar as the Default Layout of the Desktop App

Restore the project-list + session-list sidebar as a permanent column fixed within the layout flow (rather than a floating overlay), so that switching sessions does not cover content and project and agent status can always be monitored at a glance.

5.2 Acceptable Compromise: Provide a Layout Toggle Option

If the team still believes top tabs have value for some users, it should at least provide a “Sidebar / Top Tabs” layout toggle and allow users to set the sidebar as the default. Multiple community issues already point to the same request, including “Bring back the original left sidebar,” “Restore the legacy UI with the persistent left sidebar as an option,” and “Add a persistent left sidebar layout option to the new UI.” Some users have even maintained an unofficial Windows build that restores the old layout as an interim solution. The very fact that users are restoring the old UI themselves demonstrates the reality and urgency of this need.

5.3 If the Top-Tabs Direction Is Retained, at Least Restore the Sidebar’s Overview Capability in the New Layout

If the classic sidebar is ultimately not restored, the new layout needs to provide an equivalent “project–session tree” side panel that shows active sessions under each project and their agent running status, rather than compressing all sessions into a single unscannable row of tabs at the top. Otherwise, multi-project and multi-agent workflows will remain in a degraded state where structure can only be maintained through memory and naming.

6. Conclusion

The sidebar is not an “outdated UI element.” It is the most economical way to organize a complex workflow on a two-dimensional plane: the vertical axis carries hierarchy, and the horizontal axis is left for content. Once the number of sessions exceeds single digits, top tabs structurally lose the ability to provide overview, grouping, and status display. Please restore the sidebar as an available option. Do not let a change made in pursuit of a cleaner interface become a daily efficiency cost for professional users.