Changing where perspectives open
  You can change the default behavior for how perspectives are opened in the Workbench.
  
    - Open the 
     General > Perspectives
    preference page. General > Perspectives
    preference page.
- Select either In the same window or In a new window from the Open a new perspective
    group.
- Click OK.
Perspectives
  Opening perspectives
  Specifying the default perspective
  Switching between perspectives
  Showing and hiding menu items and toolbar buttons
  Configuring perspective command groups
  Configuring perspective shortcuts