PerspectiveBars extension point allows extensions to hide menubar, coolbar, statusline, prespectivebar, fastviewbar, and progress indicator. Extensions cannot affect these components if they are not created by the running application and its IWorkbenchWindowConfigurer. [Enter the first release in which this extension point appears.] [Enter extension point usage example here.] [Enter API information here.] [Enter information about supplied implementation of this extension point.]