---
title: "Validation (Box period change)."
canonical: "https://support.appfire.com/space/DLP/298355110/Validation%20(Box%20period%20change)."
format: markdown
---
> Macro (toc)

## Introduction

Changes in the Box start/end date trigger a validation check. 

## Sequentiality

[Sequentiality](https://appfire.atlassian.net/wiki/spaces/DLP/pages/297636248) settings affect same-level Boxes (can potentially prevent Box periods from overlapping). 

**Auto bottom-up** and **auto scope-based** Boxes are <u>never</u> sequential - they can always overlap.  


> ℹ️ <span style="color: #333333">Only "</span><span style="color: #333333">**manual**</span><span style="color: #333333">" and "</span><span style="color: #333333">**auto top-down**</span><span style="color: #333333">" Boxes can be sequential - if set to 'sequential', same level sequential Boxes can't overlap. </span>
> ℹ️ 
> ℹ️ ![image](media://35eb9d05-48f5-4c5c-a22d-8c314f2779ac)

## Period mode

[Box type period mode](https://wiki.softwareplant.com/doc/all/administration/box-types/general/advanced#GeneralAdvancedadministrationBoxtypes-PeriodMode) can affect if a new child Box can be created with a specified start/date. 

### Period of a Box vs period mode of its sub-Boxes

Boxes in an "auto bottom-up" period mode are affected by the period of their children (regardless of a child period mode).

### Period of a Box vs period mode of its parent

- **An "auto top-down" parent** →
  - **limits the period of an "auto top-down" child Box **
  - child Boxes in "manual"/ "auto scope-based" period mode are not affected
  - "auto bottom-up" child overrides an "auto top-down" parent

Effects of the parent Box period mode on a child Box period are outlined in the table below.

| **Parent Box → ** | **Box period** |
| --- | --- |
| auto bottom-up | unaffected (regardless of child period mode) |
| auto scope-based | unaffected (regardless of child period mode) |
| auto top-down | **An "auto top-down" parent limits the period of an "auto top-down" child**<br>Period of an "auto bottom-up" child unaffected ("auto bottom-up" child has priority over an auto "top-down parent")<br>Periods of "manual" and "auto scope-based" Boxes unaffected |
| manual | unaffected (regardless of child period mode) |