firefox and thunderbird accessiblity

Hello list,

I know this is the gnome accessibility list. i have a question about the 
accessibility of firefox and thunderbird.  under Gnome these are very 
accessible. But I've managed to get SFCE 4.10 to be very accessible and 
the two programs that are giving me trouble are firefox and thunderbird. 
When I open either one of these Orca stops working and can't read 
anything within these apps. But when I close them then Orca continues to 
work. The menu of XFCE is accessible and most of the apps within the 
menu are  accessible to Orca but I can't figure out what is stopping 
firefox and thunderbird from being accessible. Does anyone have any 
ideas? Any help would be much appreciated. I'm running xubuntu 12.10 and 
when I installed the Gnome desktop and logged into gnome firefox and 
thunderbird worked with Orca. Then I logged out and back into XFCE and 
both were inaccessible again. I think I'm missing something from 
starting up at boot but I'm not sure what it could be thanks for your 
time and help.