I’m a newbie to Adobe Illustrator CS6. One day when I work with it, I found an issue that is my gradient tool has blocked or I should say not work. After I consult my friend about this case, I know how to solve it:
When you select a object, check your appearance window before select gradient tool, you must select “Fill” path to enable gradient tool like the image shown below:
This is how I solved it! If you have any enquiries, feel free to ask me and leave comment down here.