on large images with a mask applied, CosmeticCorrection throws an "incompatible mask geometry" dialog box and then locks the view being executed on forever, as well as keeping the RT preview busy forever.
steps to reproduce:
using MacOSX PI 1.8.8-4,
NewImage, size of 5976x3840, 3 channels
extract L from this image
mask the image with the L
open CosmeticCorrection and select "Auto detect" with "Hot Sigma" of 3.0
open RT preview. the machine will think hard for a while and then exhibit the behavior described above.