Whatever i paste, ckeditor load the cache .css once

i've defined two custom css files for my ckeditor,
By using http watch basic ( a monitor tool for checking request etc. )

once i copy and paste content into my ckeditor, it shows getting the cached css file...
which slow down the performance a bit.

so i wana know whether can disable this property or not .

the exactly wording should be like this:

three files(editor.css, customized.css x2) are get from cache once i press font family, font size or text color .

I would like to disable this behaviour from ckeditor.

ps: ckeditor3.6
ie8
window xp sp3