Many people experience display problems as they start to customize their template files. A good piece of advice is to use this link below to validate your code. In many cases, getting rid of XHTML validation errors will help you solve your problem. The W3C Markup Validation Service Start by validating an empty page (so there is no content in the layout - just the layout itself - make your home page blank for example but do keep a back up of the home pages contents of course). This way you can rid your self of any errors present in the layout.tpl file which are going to appear on every page and just make matters more confusing. It will also help to eradicate interactions which may appear when content is placed into the layout. Finally, you can then test individual pages that are creating display problems and you will know immediately in which template file they reside. Secondly, I highly recommend the Web Developer plugin for Firefox. This free tool allows you to highlight css on your pages, modify it and try it out without actually modifying your site, change your xhtml source to try it out , etc. Too much to describe here but it s one of the most useful tools around. Firebug for Firefox is another great tool. It is a small investment to learn these tools and save yourself lots of time.
