If you set the number of keywords per page to 10 and there are 14 keywords starting with the same letter, it will show only the first 10 keywords in case you click on the character.
For example my VISA Lexicon has more the 10 items starting with an I If you click on I it wil only show the first 10 keywords. If I change keywords per page to 12, it will show 12 keywords but not the remaining.
There is no possibility to go to a second or third page.
If you click ALL you can see all keywords just fine.
(To show all keywords per letter you have to set the number to 25 (or more) as there is no letter with more then 25 keywords in my case.)