octobercms/october · error · SystemException

Treeview branch drag and drop Custom mode cannot be combined

Error message

Treeview branch drag and drop Custom mode cannot be combined with other modes

What it means

Error "Treeview branch drag and drop Custom mode cannot be combined with other modes" thrown in octobercms/october.

Source

Thrown at modules/backend/vuecomponents/treeview/NodeDefinition.php:313

    {
        $this->sortBy = $sortBy;

        return $this;
    }

    /**
     * Sets tree branch drag and drop mode - sort, move (or both), or custom.
     * Only the root node drag and drop mode is considered.
     */
    public function setDragAndDropMode(array $mode)
    {
        foreach ($mode as $option) {
            if (!in_array($option, [self::DND_MOVE, self::DND_SORT, self::DND_CUSTOM, self::DND_CUSTOM_EXTERNAL])) {
                throw new SystemException('Invalid treeview branch drag and drop mode: '.$option);
            }

            if ($option === self::DND_CUSTOM && count($mode) > 1) {
                throw new SystemException('Treeview branch drag and drop Custom mode cannot be combined with other modes');
            }
        }

        if ($this->groupBy) {
            throw new SystemException('Drag and drop is not supported for treeview branches with enabled Group By feature');
        }

        $this->dragAndDropMode = $mode;

        return $this;
    }

    /**
     * Sets optional grouping for a tree branch.
     * Applies to root nodes only. Allows to group
     * child nodes using a userData object property.
     * Supported for the list display mode only.
     */

View on GitHub (pinned to b608633a7e)

When it happens

Trigger: Thrown at modules/backend/vuecomponents/treeview/NodeDefinition.php:313 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/4ab4204cb8cdca09. Report an issue: GitHub.