Mosaic Layout

Every other layout in 1DevTool puts panels into fixed slots: a left sidebar, a center, a right rail. Mosaic throws the slots away. The sidebars disappear and the window becomes a tree of tiles that you split, stack, and resize wherever you want them.

Pick Mosaic in the layout picker in the header. It sits under Tiling rather than with the panel presets, so it is not mistaken for another sidebar arrangement.

Everything is a tile

Terminals, the editor, the browser, the database client, the HTTP client, Mission Control, Git — every tool you already have becomes a tile. There is no separate list of "tileable" panels.

Add one with Cmd+Shift+N / Ctrl+Shift+N, or from the + on the tile bar. The picker is a single searchable list holding three kinds of thing:

• Tools — the panels you know from the other layouts
• The terminals already open in this project — put a specific agent where you want it
• New terminal… — opens the Add Terminal dialog and drops the result into the tile you were on

Splitting, stacking, resizing

• Split a tile left, right, up, or down and the space divides between the two.
• Stack by dragging one tile onto another — they become tabs sharing a single frame.
• Resize by dragging the seam between two tiles. Seams are draggable at every depth of the tree.
• Magnify to blow the tile you are working in up to the full window, and again to put it back. The other tiles keep running underneath; magnifying is a view change, not a close.
• Close the focused tile. The terminal inside it keeps running.

Rearranging never restarts anything. Splitting, moving, resizing, and magnifying leave running agents, their PTYs, and their scrollback completely untouched — a Codex session mid-run does not notice that you moved it.

Several arrangements per project

One project can hold more than one Mosaic workspace. Name the arrangement you have now, add a second one, and switch between them from the tile bar.

This is the practical answer to "I need a different window for debugging than for writing": a Build workspace with editor + terminal + browser, and a Debug workspace with logs + database + HTTP client, both alive, one click apart.

Mosaic keeps its own storage separate from the slot-based layouts, so switching to Mosaic and back to Default never disturbs the seven panel presets you can return to.

Keyboard

Mosaic ships nine shortcuts of its own. They only apply while Mosaic is the active layout, so they never collide with the ones you use in Default or Classic.

Rebind any of them from Settings → Keyboard Shortcuts.

Related

• Layout Modes — the slot-based presets Mosaic sits beside
• Vibe Coder — the other non-slot layout
• Keyboard Shortcuts