System Settings

There are a few configuration options for Preview within System Settings

preview.enabled
type: boolean
default: true

This is a global override to enable Preview functionality. Setting this to false will disable Preview entirely.
preview.duplicateFirstRevision
type: boolean
default: true

When the first revision is created on an existing resource - do we create a "backup" copy of the published resource. This will in effect create two revisions and set one to "active".
preview.frontendEnabled
type: boolean
default: true

Override to enable/disable the menu bar on page view within normal context (when logged into the manager). The menu bar will still exist on the compare page.
preview.resourceHolder
type: json
default: {}

Holds an object mapping every context to a specific unpublished hidden resource allowing for the revisions to be stored as children. This shouldn't need to be changed as it is handled by Preview itself
preview.previewKey
type: string
default: MODXpreview

Querystring parameter to use for handling which Preview revision is displayed.
preview.compareKey
type: string
default: MODXcompare

Querystring parameter to use for handling which Preview revision is compared to.
preview.compareMode
type: string
default: MODXcompareMode

Querystring parameter to look for on revision comparison mode.
preview.disableExclusionList
type: comma seperated string
default: preview-combo-revisionStatuses,modx-resource-published,modx-resource-alias,modx-resource-link-attributes,modx-resource-hidemenu,modx-resource-published,modx-resource-parent,modx-resource-class-key,modx-resource-content-type,modx-resource-content-dispo,modx-resource-menuindex,modx-resource-publishedon,modx-resource-pub-date,modx-resource-unpub-date,modx-resource-isfolder,modx-resource-searchable,modx-resource-richtext,modx-resource-cacheable,modx-resource-syncsite,modx-resource-deleted,modx-resource-uri-override,modx-resource-uri

All core MODX manager fields with ids seperated in this list will not be disabled on a parent resource update screen.
preview.disableAdditionalFields
type: comma seperated string
default:

Any additional field IDs to disable on the parent resource. This would work well with any additional Extras that are installed.
preview.disableRevisionList
type: comma seperated string
default: modx-resource-alias,modx-resource-published,modx-resource-unpub-date,modx-resource-uri-override,modx-resource-parent

List of fields to disable on parent resource