If you convert a document from 2015 or prior to Vectorworks 2016 format, and your Window objects with a Custom Sash appear incorrectly, this can sometimes be a result of the conversion process. To correct this manually, open the document in 2016 where the custom sashes are showing incorrectly, then run the attached script via
Tools > Plug-ins > Run Script
then select the attached txt file and it will correct all of the Windows with a Custom Sash configuration in the current document. This problem will be fixed in the next service pack.
Edited by JimW