Here's a behaviour you'll want to look out for if you're going to use the Batch Rename feature when you're working with Workgroup Referenced (WGR) files using the Layout Import method.
When you rename a Class in your original file (and then update your WGR file) that Class will be added to the WGR file, not updated.
So you end up with two Classes in your WGR file, rather than a single updated Class.
This results in any objects associated with that Class being effectively switched off in any existing Viewports you have in the WGR file.
This is particularly apparent if using the Batch Rename feature to rename all Classes, as it results in Viewports going blank.
The way around this is to Batch Rename the Classes in the WGR file first. You have to rename the Classes in both files and you have to do the WGR first.