The AllowViewDrawingLayers method determines which roles have access to the displayed drawing layers. Limiting access prevents users from changing the layer displays in AutoCAD files, preserving the proper approved state of the file if other layers contain unapproved or historical information that is no longer relevant. By default, users can access the displayed drawing layers as long as they have access to methods in the MarkupView access group.
The AllowViewDrawingLayers method is delivered in the MarkupView access group. To change the default behavior, you can prohibit users from accessing
the drawing layers by restricting their access to the AllowViewDrawingLayers method. Restricting access to the method removes the Show Layers button 
from the SmartPlant Markup Plus view.