interface focus and tabbing

With LWM I can't seem to find a way to handle tabbing between interface 
elements except for text fields. For example, I have a simple interface 
with one text-input-pane and one multi-column-list-panel. When the 
focus is with the text-input-pane and the user hits the tab key, the 
focus does not change even though the multi-column-list-panel was 
created with :accepts-focus-p (the only way to give focus to the list 
panel is to click on it). I tried using the :completion-function with 
the text-input-pane and as best I can tell it never gets called when 
the tab key is pressed. I also want to return focus from the list panel 
back to the text-input-pane when the tab key is pressed. Is there a way 
to accomplish this with capi?

Thanks,

John DeSoi, Ph.D.