It seesm the local SDK help using a font that is not Asian character friendly. My Windows 8.1 regional setting non-unicode character is Tawian, I select Help > Browse Help locally, some characters and images cannot display properly.
For instance, I will see something like this.
In the jMonkeyEngine SDK :
Choose File???New Project??? from the main menu.
Choose New???Java Class to create a new file.
The Netbeans help is fine and the fonts looks better.