Question: Rather than show a confirmation dialogue when someone wants to archive a project (each row in the animation is a 'project'), I've decided to immediately archive, with the option to undo.

My question is, should this row disappear after a certain time? Or should it persist until the user visits another screen?

[![Archiving a row](https://i.stack.imgur.com/gxZEf.gif)](https://i.stack.imgur.com/gxZEf.gif)

Answer: 
I suggest you keep the item in the list, with a notice it is archived and a button to Undo, but occupying the same height it has right now and modifying the item rather than adding an extra line. This way the user can:

* archive several projects
* decide to Undo any of those without having to change multiple times of screen
* keep the layout with the same height
* have the archived item with a different style (because right now archived/non-archived items look the same)

> 
> **Project 1**
> 
> 
> Project 2 archived. **Undo**
> 
> 
> **Project 3**
> 
> 
> **Project 4**
> 
> 
>
Based on the following :

* **Consistency**. Keep the message always in the same possition. Also, this kind of modelles feedback is usually located on the top (see gmail).
* **Relevancy**. The message should be visible only for as long it is relevant, otherwise it is noise to the user. It will not be relevant when the user switches to another task.

I recommend :

Display the message always on the top of the block. Hide the message after 20 seconds or when the user performs another action (change screen, select another item etc).