The gradient mixer tool lets you draw gradients across layers or selections and also fill text and shapes with gradient. Shortcut key is ()
How to use: Gradient mixer tool is placed under the gradient swatch tool and is the third tool on the right tool bar. Using this tool you can create infinite colour combinations of gradients to fill colours to the design you create. You can see colour bar where you can add different colour nods. You can click on the nods to change the desired colour from colour cooler. You have panel from where you can add a nod and close it. There are two types of gradient forms which you can give. One is linear and the other is radial. You even have angle selection tool where you can change the angle of the gradient.