I'm using my IDEAmacs all the time, but when I try it in 825, I'm getting a lot of problems.
It would appear that the code that goes inside the .runWriteAction() is not recognised as a change to the buffer. The result is that undo operations get completely screwed up, and the Local VCS don't see these changes at all! As you can understand this causes no end of problems.
The code for the offending action is here:
Is this a bug in 825 or the plugin code?