Described is a mechanism that preserves the state of computer system shared resources and/or settings, and ensures that changes thereto are reverted when an application exits. A shared resource change bubble logically surrounds application code that causes system resource and/or setting data to change. The bubble preserves existing data before it gets changed, and restores the data when the application program code exits. In one implementation, the bubble is implemented as a library loaded by the application. In an alternative implementation, the bubble is run in a separate process, whereby the bubble can restore changed data even if the application program crashes. In another implementation, a bubble is automatically run for any application that the user has specified needs a bubble. Multiple settings and states may be preserved in a bubble for multiple applications, allowing changes to be undone and reapplied per application, e.g., whenever focus changes.