… And listen to your customers.“ So Keith had a good point in telling me that version 0.4.1pre2 destroys the HeaderView. Yes, I managed to read all headers without any other extension in 0.4.1pre2, but ignored existent (already showed) mail headers. Cause the extension adds new headers to the HeaderView and hides them, also existent Headers where hidden.

So, repaired this one and the now released pre-version 0.4.1pre3 should solve the problem. Thanks Keith (and all the others) for testing and reporting.