CKEditor not editable in Contributor UI

Hello, in the Contributor UI CKEditor is not editable. No errors in the log for even TRACE . I checked all the code, ckeditor plugins under CS app. They all look fine, BUt when I click on the CKEditor text area in the Edit mode nothing happens. In normal working environment, it should open the CKEditor, but in my env it does nothing. Any ideas? Even I updated CKEditor.jsp LAZY LOAD to false, but it didn't help.