My company was quite successful in creating an aircraft mission planning system using the Eclipse RCP infrastructure. There were some troubles (mainly the fact that the new interfaces you should use are not very well documented), but it gave us a huge foot and provided a lot of useful archeology.
In many ways, we are just an editor, but instead of a text file, you are modifying a database describing a mission with an airplane, and many of the interactions are through a 3D globe displayed in the view. Data binding helps to constantly synchronize various views and editors (although problems with flows between the SWT application and third-party AWT widgets using data bindings were a nightmare that I would prefer not to review)
It was a complicated program, which was mainly attended by three developers who did not know that Eclipse was going to write in about a year. Today we are expanding it to other customers by adding additional plugins.
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