In addition to opening files through the Application menu, or from the Quick Access Toolbar, you can also open files from the development areas in the Configured Environments tree.
Note: Files can only be opened in one area of Developer Workbench at a time to ensure that your changes are not overwritten by another opened version of the file. However, you are able to open a file in Developer Workbench and in a Windows Associated Tool at the same time. To ensure that your changes are saved properly, you should only modify one opened version of the file at a time.