X-Assist is a lightweight desktop enhancement application that will enable you to bring back some of the OS9 windowing functionality. X-Assist was designed with the purpose of allowing OS9 fans to use some of the OS9 functions that were removed in the OSX.
The first function reinstituted by X-Assist is the "Application Switcher Menu" that allows you to quickly visualize and select the opened applications if you want to use them from the top right corner of screen. This function was replaced in OSX by the Dock but there are still users that prefer the old configuration. The windowing functionality from OS9 is also brought back by X-Assist thus allowing you to easily switch between modes. In OS9 the window behavior allowed you to switch between applications by clicking the respective window reveling all the open windows for that application which changed in OSX and offered some users discomfort. There are other functions that have been "resurrected" by X-Assist, such as: easy access to System Preferences, fast access to Recent Applications, add hierarchy into a "Shortcuts" sub-menu and extensible Control Strip. Also, X-Assist provides support for the Objective-C (NSBundle), SetVolume and MP3 Player plugins.
In conclusion, X-Assist is a compact desktop enhancement utility that will allow you to use some handy OS9 features in OSX, such as: Application Switcher Menu, extensible Control Strip, OS 9 window behavior and many more.