These days virtually all my work on XPages and Custom Controls is done in the source pane. But by default when you open the design elements, they open to the Design pane.
Wouldn’t it be great if it opened to the Source pane?
The good thing about the Package Explorer is that by right-clicking on a design element you can change the editor to launch. If you choose the XML Editor, then it launches the normal editor, but with the XML Source pane displayed.
There’s a bit of a trade-off here, in that you have to expand the XPages folder in the navigator rather than clicking on XPages in the Application Navigator and getting a view in the central pane. If you have a lot of XPages, that takes up a lot of space. And if you’re coding your business logic in Java, it means a lot of scrolling in the Package Explorer. Furthermore, with Custom Controls, the Package Explorer displays the Custom Control and it’s xsp-config file separately. So Custom Controls take up even more space. So it depends which you prefer, but at least you have the choice.
