The XrefStates plugin can be used to simplify the use of multiple Externally Referenced drawings inside AutoCAD®. It captures the loaded/unloaded state of these Xrefs and saves them inside the drawing, just as AutoCAD's Layer feature allows you to save Layer States. This is highly beneficial for people using Xrefs to store different sets of data and wanting to move quickly between them.
This plugin was first published as an ADN Plugin of the Month. The plugin has been provided with the complete source code needed to build the application, with the intention of encouraging users of Autodesk software to use programming to tailor the products they use to their specific business needs.
More information regarding this plugin can also be found on Kean Walmsley's blog about AutoCAD programming, Through the Interface.