lockLayout Property
Sets or returns a Boolean that represents whether Web Parts within a zone can be added, deleted, resized, or moved when designing a Web Part Page inside of the browser; however, non-layout properties on Web Parts can still be changed. True indicates they cannot be added, deleted, resized, or moved.
Note The lockLayout property applies only to pages within a Web site based on Microsoft Windows SharePoint Services.
expression.lockLayout
expression Required. An expression that returns one of the objects in the Applies To list.