When I click on add new article, Joomla shows the page incompletely.
It doesn't even show the form itself completely.

Even now that I have enabled the debug mode, it doesn't show anything. I think that something die()s the process of outputting the page to the browser.
Please note that I haven't had a bad joomla installation. It was working very well a bit little ago.
I haven't also changed a deep core setting. I think that I have only changed jcomment setting that doesn't look related to the problem.
developmentin Global configuration, but doesn't still show anything - Mohammad Naji