Setting a Custom Property in a macro using "CustomPropertyManager" fails to work if the same "Name" property exists within the Custom Property Tab Builder.  The Custom Property Tab Builder appears to lock setting of properties by a macro.  After running the macro then selecting View > Properties...the value is not set.  If you run the macro then open the Custom Property Tab Builder it correctly sets the properties.

Is there some way of overcomming the locking effect of the Custom Property Tab Builder?

Dim swCustPropMgr As SolidWorks.Interop.sldworks.CustomPropertyManager

swCustPropMgr.Set("DrawnBy", "Someone Else")