Fixed Tag -dialog (special.js) to support <source lang="xxx">. .<source> definition as "fck_mw_source" element (requires extension SyntaxHighlight_GeSHi).
Errors found with IE11 native mode in wysiwyg editor: all dialogs work but they had focus problems with their respective elements on page
=> to fix this forced compatibility mode IE=9 with wysiwyg editing mode only. (WYSIWYG/CKeditor.body.php vs. includes/OutputPage.php)