# Use Previous Page In Oysterun

Oysterun's Previous Page control returns you to the Oysterun screen that most
closely matches where you came from. This page helps you predict where that
control goes after you open chats, file previews, folders, mail attachments,
profiles, settings, and other full-page views.

## Prerequisites

- You are signed in to Oysterun.
- You are already on an Oysterun page that shows the top bar Previous Page
  control, the chat header Previous Page control, or the Oysterun app back
  gesture.
- The source page still exists. For example, the Session, chat message, folder,
  mail item, or preview you came from has not been removed or become
  unavailable.

Starting screen: any Oysterun full-page view with a visible Previous Page
control, such as Chat, File Preview, Explorer, Mail detail, Scheduler log,
Session Profile, Session Loop, Settings, or a folder picker.

## Use Previous Page

Select the visible Previous Page control. In the Oysterun app, use the app back
gesture from the same screen.

Expected result: you should see the source-aware page listed below, or the
nearest safe Oysterun page when the exact source is no longer available.

## What Previous Page Opens

| Current screen | Previous Page result |
| --- | --- |
| Chat | Sessions list. |
| Chat opened from a notification, search result, pin, or focused message | Sessions list, even when the chat URL contains a focused message. |
| File Preview opened from a chat message with a saved message source | The same chat, focused near the message that contained the file or folder link. |
| File Preview opened from a chat link without a saved message source | The same chat. |
| File Preview opened from Explorer | The Explorer folder and route context that opened the file. |
| File Preview opened from Mail detail | The Mail detail page that opened the attachment or linked file. |
| File Preview opened from another File Preview | The prior File Preview page. |
| File Preview opened directly without a source | Explorer for the containing folder when Oysterun can identify it. |
| Explorer folder opened from a chat message with a saved message source | The same chat, focused near the message that contained the folder link. |
| Explorer folder opened from chat without a saved message source | The same chat. |
| Folder picker | The page or dialog that opened the picker. |
| Mail detail | The Mail list you were viewing. |
| Scheduler log | The Scheduler page. |
| Session Profile | The Session chat or Session page that opened the profile. |
| Session Loop | The Session page that opened the loop view. |
| Settings | The page that opened Settings, or the main Oysterun Sessions view. |

Oysterun uses a saved Oysterun route for these returns instead of relying only
on browser history. Reloading the page, opening a direct URL, restoring the
Oysterun app, or resuming a WebView should still keep the Previous Page result
within Oysterun when the saved route is valid.

## File Preview Return Details

File Preview accepts only safe Oysterun return targets. A valid return target
must stay on the current Host and must point to a supported Oysterun app page.
Oysterun rejects external websites, unsupported app paths, browser-only pages,
self-repeating File Preview targets, and return targets for a different
Session.

When you open a local file or folder link from chat, the visible text remains
the file or folder label. Hidden return details are not shown in the message
text. After you open the link, Previous Page should still return to the chat or
folder that opened it.

Checkpoint: the File Preview header shows the previewed file, and Previous Page
returns to the expected chat, folder, mail detail, or prior preview without
opening an external website.

## Chat Return Details

Chat always returns to the Sessions list from the top bar Previous Page control
or the Oysterun app back gesture. This is also true when Chat was opened from a
complete-message notification, a search result, a pinned message, or another
focused-message route.

Message controls such as Jump to Unread and Mark as Read are separate timeline
actions. They do not change where Previous Page goes.

Checkpoint: after you leave Chat with Previous Page, the Sessions list is
visible and the chat is not stacked as another browser-history layer.

## When Previous Page Cannot Use The Exact Source

Oysterun falls back to the nearest safe Oysterun destination when the original
source is unavailable or unsafe to reuse.

Bounded recovery:

1. Check whether you are still signed in. If the login screen appears, sign in
   and reopen the page from the normal Oysterun navigation.
2. If a File Preview cannot return to the exact source, open Explorer and go to
   the containing folder.
3. If a chat, mail item, Session, or Scheduler entry is no longer available,
   return to the Sessions, Mail, or Scheduler list and reopen the item if it
   still exists.
4. If Previous Page would leave Oysterun or repeat the same unavailable screen,
   use the main Oysterun navigation instead of retrying the same control.