Version conflicts

Summary

When this browser has a newer autosaved design than what's currently loaded, Blotter Builder shows the same Recover unsaved design? dialog covered in Device recovery — this is also the app's version-conflict mechanism. It only checks at load time. Two tabs open at once do not warn each other about conflicting edits; the last one to autosave silently wins.

Use it when

• You understand this article when working across multiple tabs or windows of the editor at once, or when you're unsure why a reload showed a design you didn't expect.

Before you begin

Nothing to prepare — this is about how the app behaves, not a feature you turn on.

Steps

There's no separate "resolve conflict" workflow — conflict handling is the Recover unsaved design? dialog:

1. If you open or reload the editor and this browser has a saved snapshot newer than what's currently loaded, the dialog appears.
2. Select Restore recovered design to load that newer snapshot, or Discard recovery / Not now as covered in Device recovery.

What changes

• This was tested directly with two tabs of the same browser open at once: Tab A had one design; Tab B (opened fresh) was shown the same recovery dialog referencing Tab A's save, dismissed it, and built a different design. Reloading Tab A then correctly showed the recovery dialog for Tab B's newer save, and Restore recovered design loaded it accurately.
• Conflict detection only happens when a tab loads or reloads — it compares the browser's saved snapshot against what that tab is about to show. It does not run continuously while a tab stays open.
• Confirmed directly: with both tabs still open (neither reloaded), making a further edit in Tab B produced no warning of any kind in either tab — Tab B's autosave silently overwrote the shared saved snapshot. Reloading Tab A after that showed a new recovery dialog for Tab B's latest state, with no indication that anything had been overwritten in between.

Print note

Not applicable — this is entirely about which design state is loaded into the editor, not about export or print output.

Warnings and limits

• If you work in two tabs or windows of the editor at the same time on this device, the version that autosaves last silently wins — there is no live conflict warning while both stay open. If you want to work on two different designs at once safely, use Export PNG, an export, or a signed-in account's cloud drafts to keep them distinctly saved, rather than relying on two open tabs.
• This article covers local, same-device conflicts only (confirmed directly, via two tabs sharing this browser's storage). Whether or how conflicts are detected between a signed-in account's cloud draft and a local device recovery snapshot was not tested — see Cloud drafts and accounts for what's unverified there.
• There is no version history or ability to see what was in a snapshot before it was overwritten — once a newer autosave replaces the shared local snapshot, the previous version is gone unless it was separately exported or saved.

Desktop and mobile

The underlying mechanism (autosave plus the recovery dialog) is shared code confirmed identical between desktop and mobile in Device recovery — there is no separate mobile-specific conflict behavior.

Troubleshooting

Related topics

• Device recovery
• Cloud drafts and accounts
• Classic, Wide & Hexagon formats
• Undo, redo, fit & recenter

Verification note

Verified against Blotter Builder on 2026-07-22.

Source notes

Primary observations — from the live application at https://blotterbuilder.tdl.fyi, 2026-07-22, using two browser tabs of the same origin (sharing IndexedDB storage) to directly exercise concurrent-editing behavior, rather than inferring it from a single tab.

• Observed — Tab A built a one-shape design and let it autosave. Tab B, opened fresh, showed the Recover unsaved design? dialog referencing Tab A's save; selecting Not now in Tab B, then drawing a different shape there, left Tab A unaffected until reloaded.
• Observed — reloading Tab A after Tab B's edit showed the recovery dialog with Tab B's save timestamp; selecting Restore recovered design loaded Tab B's shape correctly into Tab A.
• Observed — with Tab A now showing Tab B's restored design, and Tab B still open (not reloaded) with its own in-memory state, drawing a second shape in Tab B produced no dialog, warning, or any visible indication in either tab. Reading the shared IndexedDB record directly afterward confirmed it held Tab B's two-shape state, silently overwriting whatever Tab A had a moment before.
• Observed — reloading Tab A again at that point showed a further recovery dialog for Tab B's newest (two-shape) save — confirming detection only triggers at load/reload time, not continuously.

Verification log