octobercms/october · error · ApplicationException

The selected class doesn't exist.

Error message

The selected class doesn't exist.

What it means

Error "The selected class doesn't exist." thrown in octobercms/october.

Source

Thrown at modules/backend/widgets/ReportContainer.php:254

    /**
     * onAddWidget
     */
    public function onAddWidget()
    {
        if (!$this->showAddRemove) {
            throw new ForbiddenException;
        }

        $className = trim(Request::input('className'));
        $size = trim(Request::input('size'));

        if (!$className) {
            throw new ApplicationException("Please select a widget to add.");
        }

        if (!class_exists($className)) {
            throw new ApplicationException("The selected class doesn't exist.");
        }

        $widget = new $className($this->controller);
        if (!($widget instanceof \Backend\Classes\ReportWidgetBase)) {
            throw new ApplicationException("The selected class is not a report widget.");
        }

        $widgetInfo = $this->addWidget($widget, $size);

        return [
            '@#'.$this->getId('container-list') => $this->makePartial('widget', [
                'widget' => $widget,
                'widgetAlias' => $widgetInfo['alias'],
                'sortOrder' => $widgetInfo['sortOrder']
            ])
        ];
    }

View on GitHub (pinned to b608633a7e)

When it happens

Trigger: Thrown at modules/backend/widgets/ReportContainer.php:254 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of octobercms/october@b608633a7e (2026-08-21). Data as JSON: /api/errors/f24ee8b98ca2679c. Report an issue: GitHub.