The first time I encountered with a problem on Drupal.
Views Module - changing , for example , fields, is changes are not applied . When configuring fields are not collapsed Rewrite results, Style settings , etc.. (In the legend missing "a" tag)
I suppose that this happened after the installation of the module fancybox . At the time when I discovered the problem, fancybox was "integrated" into the site.
I'm not sure what is to blame fancybox . But it is the only module that was installed recently ( of course, with jquery_update and itself a plugin)
Q: how to solve such a problem? After removal views will be removed all generated views. A removal fancybox - will be disabled all pop-up windows in most of the materials.
How to identify "a causer" of a problem (in general)?