CKEditor 4.3.4 and Ajax Modal Popup malfunction styles, colors, etc. on Chrome and Firefox

Hi, meanwhile I apologize if the topic was already discussed, but I could not find a solution to this problem: using Asp.net 4.0 framework. 

On page I inserted an ajax ModalPopupExtender which contains, inter alia, a control ckeditor. 
IE compatibility view Ver.11 and working properly (strangely), but if I open the same page with Mozilla Firefox and Chrome ckeditor control is not working properly, in particular, styles, colors, formatting, fonts, etc.. are not active. 

The controls ckeditor outside of Ajax ModalPopup, however, are working properly. 
Finally, using the precise debugger respective browser known errors