If you work a lot with complex ADF pages in JDeveloper, you may get tired of waiting for it to open your pages in the Design view, I know I do!  Fortunately, there is a simple solution.  You can change the default editor so that they will open in source view (which is very fast) and then you can switch to design view only when you actually want to.

To do this, select Preferences from the Tools menu, then select File Types in the navigation tree on the left hand side.  Open the Default Editors tab on the right, find JSP Source and change the default editor to Source using the drop down box at the bottom.  Then click on OK.

You can also do this for other types of files.