I’m using the Captcha anti-comment-spamming-engine in my blog:
Some of you complained that after posting a comment you can’t see it afterwards. This is caused due to a time mechanism plugged in the Captcha engine – after X seconds, the code becomes invalid and you have to insert a new one. In case that the Captcha will have code timeout – it will make you enter a new generated code simply by leaving you on the same page. So please make sure that after hitting the “Save Comment” you’re on the main page and you don’t have your comment at the bottom of the page, if so – enter the new code and click the “Save Comment”.