Change the movement angle and wideness at the Direction panel. Setting the pointer to its maximum radius at the axis (0°,90°,180° and 270°) amplifies the wideness to 100% of the texture's width or height.

For more control over the movement radius, the wideness is scaled by the Amplify value.

If you have defined a Source Texture, the shifting radius is modulated with its heightmap. This can be used for distortion effects like that visible at Image 2. The best results can be achieved with the Smoothing value set to high numbers.

The Bias value comes only into play if you utilitize the heightmap option. It's a constant number that is added to the shifting amplitude, which allows you to let pixels move in divergent directions (with e.g., negative bias values).

Image 3 for instance was created by shifting it with itself being set as heightmap and a Bias value of -50.