Enable Autopan

From the main menu, choose Options -->Enable Autopan (Note: Please make sure this is checked)

If this option is selected, the capture area will follow the cursor to wherever it goes during recording. This has the effect of making the screen capture to occur at the region with the most action.

Autopan Speed

Now, from the Main Menu, choose Options --> Autopan Speed

Use this to control the maximum speed at which the capture area follows the mouse. The value is measured in screen pixels.