[orca-list] pauses when navigating in the key bindings page tab

[José Vilmar Estácio de Souza <vilmar informal com br>]

Hi all.
Using latest orca built from git I found that there are pauses when 
scrolling in orca key bindings page tab.

To reproduce try the following:
1. Press orca_key+space.
2. Go to the key bindings page.
3. Press tab until you find the function table.
4. Press down arrow.
In my machine orca reads some functions and pauses for a while.
I have to wait about 15 seconds before the orca back to talk.
Thanks.

--
{}S José Vilmar Estácio de Souza