Upon launch, the colour module blinks the mask three times in the familiar way. If a full mask is not set, the Color modules allows you to set it now, as colour balancing is typically applied to the full image (requiring a full mask).
In addition to blinking the mask, the Color module also analyses the image and sets the Red Bias Reduce, Green Bias Reduce and Blue Bias Reduce factors to an value which it deems the most appropriate for your image. This behaviour is identical to manually clicking the 'Sample' button.
You can convert everything you see to a format you find convenient. Give it a try!