AdHoc attributes on WTParts cannot be updated using the Update Multiple Objects functionality on Windchill PDMlink 10.1. Business needs to always either use Product Structure explorer or Spreadsheet to add/edit ad hoc attributes. But in WC9.0 it was fairly simpler with a view creared in the workspace.
It would be a very good feature If the Ad-hoc attributes on WtParts could be edited in the user's workspace. Attached is a Video of the same. Please take a look at it.