With "external viewer" it works fine. But there is a problem with the pdf viewer that it shows the text too wide, there is something wrong with it. What should I do?
You don't use the good version of Texmaker. You must use the TexmakerMacosx64.zip package and not the TexmakerMacosxLion.zip one (TexmakerMacosxLion is for pure MacOsx Lion system )