# "Class "Concrete\\Core\\Panel\\PanelController" not found"

**URL:** https://forums.concretecms.org/t/class-concrete-core-panel-panelcontroller-not-found/9016
**Category:** Developing with Concrete
**Created:** [April 22, 2025, 10:36pm UTC](https://forums.concretecms.org/t/class-concrete-core-panel-panelcontroller-not-found/9016 "2025-04-22T22:36:56Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![karlfriend.nz](https://forums.concretecms.org/user_avatar/forums.concretecms.org/karlfriend.nz/32/5178_2.png) [@karlfriend.nz](https://forums.concretecms.org/u/karlfriend.nz)
#### Post date: [April 22, 2025, 10:36pm UTC](https://forums.concretecms.org/t/class-concrete-core-panel-panelcontroller-not-found/9016/1 "2025-04-22T22:36:56Z")

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Hey there team I am trying to add a slide out panel to my package like the add content button - I have managed to get the slide out working - yay! but no content is loading - after some research and trying to load the file manually i get this returned, any ideas?

“Class “Concrete\Core\Panel\PanelController” not found”

Cheers

 ![SCR-20250423-jshq](https://forums.concretecms.org/uploads/default/original/2X/b/bd83d87e6ed0ae4494013e8ec121c25afa8686a4.png)

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### Author: ![mnakalay](https://forums.concretecms.org/user_avatar/forums.concretecms.org/mnakalay/32/3625_2.png) [@mnakalay](https://forums.concretecms.org/u/mnakalay)
#### Post date: [April 23, 2025, 8:30pm UTC](https://forums.concretecms.org/t/class-concrete-core-panel-panelcontroller-not-found/9016/2 "2025-04-23T20:30:01Z")

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It’s exactly that. That class doesn’t exist.  
The panel controller classes are in Concrete\Controller\Panel but none is called PanelController.