title: how do i find out what view or editor is an active workbench page using RCP eclipse
body: <p>Many workbench APIs are accessible only from IWorkbenchWindow or IWorkbenchPage. </p>
  
  <p>My Question is 
  I am click the toolbar or Button to get which view or editor current working</p>
  
  <p>or</p>
  
  <p>find out the Active workbench page or Active workbench window using RCP eclipse.</p>