Created attachment 116382 [details] [review]
revision 1

I think this gets the job done. I've pylinted but not yet regression tested this. Assuming it doesn't blow anything up, I'll ask for testing. :-)

Passes the regression tests. Please test.

I run thunderbird all the time but don't ever remember seeing this.  How would you like me to test this? 

Start reading a message making darned sure you're somewhere in the middle of the message. Having done so, try Alt+Tabbing to some other window (doesn't seem to matter if it's the Thunderbird main window or another app). Then Alt+Tab back to the message you were reading.  At this point I would expect the speech and braille context to provide some indication of where you are (which should be the line you were on when you left the message). Without the patch, that is not the case. Then down arrow to read the next line. One would of course expect have Orca present that next line. Without the patch, it does not. At least that's been my experience working on this bug. :-)

Thanks!

Ah now I see.  Yes this works nicely.  

Thanks Mike! Patch committed to trunk, moving to pending.

*** Bug 547467 has been marked as a duplicate of this bug. ***