Any removed energy, is collected per pixel and re-distributed across the image in a second pass, giving the user intuitive control, via the 'Grain Dispersion' parameter, over a hard upper size limit beyond which grain is no longer smoothed out.
StarTools does more than just help you make "pretty pictures".
Chances are that the image looks terrible, which is - believe it or not - the point.
To apply the new colour balance to the whole image, launch the Mask editor once more and click Clear, then click Invert to select the whole image.
The goal of color balancing in astrophotography, is achieving an accurate representation of emissions, temperatures and processes.
You can convert everything you see to a format you find convenient. Give it a try!