# Custom Block error in Panel

**URL:** <https://forum.getkirby.com/t/custom-block-error-in-panel/32213>\
**Category:** Questions\
**Created:** [August 9, 2024, 11:48am UTC](https://forum.getkirby.com/t/custom-block-error-in-panel/32213 "2024-08-09T11:48:46Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![mafleig](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.getkirby.com/mafleig/32/15806_2.png) [@mafleig](https://forum.getkirby.com/u/mafleig)\
**Post date:** [August 9, 2024, 11:48am UTC](https://forum.getkirby.com/t/custom-block-error-in-panel/32213/1 "2024-08-09T11:48:46Z")

</div>

Hi everyone,  
I created a custom block (“slider”) for my layout field but always get this error inside the panel:

**Cannot assign array to property Kirby\Cms\Fieldset::$icon of type ?string in file: […]/kirby/src/Cms/Fieldset.php line: 52**

- I have put my custom block **slider.yml** inside blueprints/blocks

```auto
name: Slider
  fields:
    sliderimages:
      type: files

```

- I have put the snippet **slider.php** inside snippets/blocks
- The Layout field in the blueprint is set up like this:

```auto
              layout:
                type: layout
                layouts:
                  - "1/1"
                  - "1/2, 1/2"
                  - "2/6, 1/6, 3/6"
                  - "1/3, 1/3, 1/3"
                  - "2/3, 1/3"
                  - "2/6, 3/6, 1/6"
                  - "1/6, 3/6, 2/6"
                fieldsets:
                  - text
                  - image
                  - slider

```

What am I missing?

---

<div class="post-metadata">

**Author:** ![texnixe](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.getkirby.com/texnixe/32/5754_2.png) [@texnixe](https://forum.getkirby.com/u/texnixe)\
**Post date:** [August 9, 2024, 12:07pm UTC](https://forum.getkirby.com/t/custom-block-error-in-panel/32213/2 "2024-08-09T12:07:50Z")

</div>

> [@mafleig](#):
>
> ```auto
> name: Slider
> fields:
> sliderimages:
> type: files
> 
> ```

Fields must not be indented here

---

<div class="post-metadata">

**Author:** ![mafleig](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.getkirby.com/mafleig/32/15806_2.png) [@mafleig](https://forum.getkirby.com/u/mafleig)\
**Post date:** [August 9, 2024, 12:31pm UTC](https://forum.getkirby.com/t/custom-block-error-in-panel/32213/3 "2024-08-09T12:31:51Z")

</div>

Oh, right! those indentations get me everytime 😅 Thanks!