Brian Teutsch, Program Manager with the Windows Sidebar Team made an entry on the Gadget Cornet Blog, introducing the API-related changes that have occurred in Windows Vista Release Candidate 1. In this context, while the majority of gadgets are unaffected by the API alterations, the operating system's evolution to a new build has impacted the performance of a few gadgets designed for Beta 2. "In the RC1 release of Windows Vista, the Sidebar received a number of changes in the APIs that make up our object model," stated Teutsch.

He summarized the changes to three steps. The Windows Sidebar Team strived for reduced complexity with the RC1, and even disallowed several APIs. Additionally, the RC1 delivers a superior level of integration in relation to Windows components. The pluses are minor in volume, Teutsch referring to them as small additions.

System.Gadget.Settings.readString and writeString are two methods introduced to increase settings storage control. Interaction between the gadget and its fly-out has been expanded via the System.Gadget.document. System resources consumption is another area were the Windows Sidebar Team boosted efficiency by allowing for off screen suspended operations with the System.Gadget.visible, visibilityChanged.

Sidebar Graphics Library, System.Contacts, System.Machine.CPUs, System.Machine.PowerStatus, System.MessageStore, System.Network.Wireless, System.Time were also API areas where enhancements were introduced, alongside with removals and simplifications. "We made a number of changes to simplify the APIs and make the information more reliable. The following removed APIs typically are exposed in other places, such as WMI (Windows Management Instrumentation) or through the Shell and FileSystemObjects for scripting, System.Net.NetworkInterface, System.RecycleBin.percentFull, System.Sound," concluded Teutsch.