WYSIWYG Editor is not refreshing when you modify font-size or font-family of some text, letting think user that it is not working

Text is not refreshing in the editor when you modify font-size or font-family, which lets the user thinks that it is not working. Actually the change appears when previewing or saving the page but not in the editor.

Steps to reproduce:

-Type some text in the wysiwyg editor
-Select this text and pick a font-size (let say 24pt)
-Result: the text's font-sizedoes not appear to have changed (it should be 24pt, but it's still the default size).

But if you preview or save, you then see that actually the font-size have been taken into acount (it is displayed at 24pt in preview and view mode, but not in the WYSIWYG editor).