I've had performance problems with Firefox and Thunderbird with Windows Speech for a while. Although both applications have some accessibility support---menus, dictating title words switches to that tab in FF, etc.---it seems to be rather hit or miss. This isn't a particularly big deal since both applications have decent keyboard support built in and FF has the mouseless browsing extension, making it pretty easy to automate these applications using Your Favorite Macro Package.

The performance was killing me though: FF started to bog down with only a few tabs open, and the name "Thunderbird" seemed like a cruel joke given how badly the application crawled. Unfortunately, the performance also disrupted macro behavior: the speech engine was constantly spinning, so macros would become erratic, sometimes even after I switched applications.

I'd guessed that the Active Accessibility was the problem: perhaps Firefox is exposing the text of *all* the hyperlinks in all open documents, not just the ones I can see right now. Whatever the cause, at some point the app would hit some sort of internal WSR threshold, after which performance would rapidly fall apart.

Nosing around in the registry this afternoon, I stumbled across the following key:

HKEY_CURRENT_USER\Software\Microsoft\Speech\Preferences\AppCompatDisableMSAA

Hello! From the existing entries, this key appears to accept string values indicating applications that should have Active Accessibility disabled. I added two new string values ("firefox.exe" and "thunderbird.exe"), restarted everything, and BAM! Looks like my computer was built this century after all!

Of course, disabling Active Accessibility disables the "built in" voice support for menus, hyperlinks, tabs, folders, etc., but given the performance difference I think that's a tradeoff I can live with.

I'm curious: have others had performance problems with these applications? Has anyone else tried this solution, and what was your experience with it?

Here are a couple of related posts:

• http://www.oldskooldeveloper.com/msgs/4/20018.aspx
• http://social.msdn.microsoft.com/Forums/en-US/wind...

This was the only information I could find; doesn't appear to be a widely discussed capability.