Number of items per page

Hi,

I have many forms. These are spread over 4 pages with 20 forms being displayed on a single page in the admin area. I would like to show all of the forms on a single page. I have tried changing the screen option settings at the top of the page, but no matter what number I enter, it reverts back to 20 items per page. I think this is a Contact Form 7 issue. Could you please let me know how to resolve this. Thanks!