i understand there is another thread with a fix but i dont understand it?

i press tab and if there is more then one person with the nick it hi-lights part of the nick in yellow and deletes it no matter what i do i have to basically type out the nick its so annoying. how do i fix it so it works properly? and usually if i press tab mote then ones its supposed the scroll through the nicks and it doesent :S

any way i can fix it?