The problem

1. Edit a .ly file
2. Save
3. Edit again

There shouldn't be any complaints just because of normal editing. Instead, the 
complaint keeps coming again and again.


Product versions:

Was using Eclipse Juno, then upgraded to Luna.
Windows 7
Xtext 2.7


Additional information:

When getting the project from git and setting up and running the project as per 
the developer instructions, the runtime environment gets Xtext 2.6 and the 
problem doesn't reproduce.

I got the idea that maybe it's about Xtext 2.7, from here:

   https://github.com/jknack/antlr4ide/issues/89
   https://www.eclipse.org/forums/index.phpt=msg&th=827695&goto=1441413&#msg_1441413

A quote from Xtext developer:

"it appears that you have more than one editor callback that tries to
register the resource at the dirty state manager. This was changed for
2.7 to be a direct support on the editor. If you have custom editor
callbacks, make sure they don't try to register the resource again."