Thread:Sweetkisa06/@comment-5818466-20130311015446/@comment-4072017-20130311165529

The complex code thing in the "Source mode required" message means there are wiki markup tags in an article that make the page uneditable in Visual mode (rich text editing). In the case of the page you've linked to me, the complex code/wiki markup here refers to the HTML comments tag located somewhere in the article.

So if you want to edit in Visual mode, that comments tag should be used only once in the article. You have to remove the said tags where it's applicable, and you may change the text inside the tag beforehand so that the text goes with the article. Unless if you don't mind doing the page editing in Source mode, you can leave some of the comments tag behind (but not too many, though).