# Renaming a document made the old one disappear, or two tabs now share the same name

**What you are seeing**

Renaming a document made the old one disappear, or two tabs now share the same name.

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## Why it happens

The title is the filename. Renaming uploads a differently-named file, and nothing checks whether a name is already in use.

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## What to do

Delete the leftover file if you renamed one, and keep titles distinct. The app will not stop you creating duplicates.

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## Settings involved

| **Setting**               | **Where**    | **What it does** |
| ------------------------- | ------------ | ---------------- |
| View / Edit (editor mode) | Editor modal | \-               |
| Title                     | Editor modal | \-               |

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## Limits that apply here

| **Limit**                | **Value**                  | **What happens**                                                                                                                                               |
| ------------------------ | -------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Document title length    | 50 characters              | Enforced by the Title input in the editor. The title becomes the attachment filename.                                                                          |
| Large document preview   | About 1,000,000 characters | Read-only previews longer than this switch to a virtualised viewer that renders in chunks as you scroll, so browser find-in-page and similar behaviour differ. |
| Simultaneous image loads | 20                         | At most 20 image URLs are resolved at once, so image-heavy documents load in waves.                                                                            |

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## A few things that catch people out

* Documents over roughly a million characters switch to a virtualised preview, so behaviour such as find-in-page differs.

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[Everything elseThe rest of this family.](https://help.gocapable.com/jira-markdown/everything-else.html)

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_Found it? Good._