RTP window never completes with ACDNR luminance mask preview

[Nocturnal]

Hi,

my steps:

- create preview
- set up ACDNR to do L masked L and C noise reduction
- check the preview button in the luminance mask section
- bring up real time preview
- slide the midtones slider back and forth
- note that the 'show transformed image' icon keeps turning and the preview never gets rendered
- snap out of it by clicking the RTP button on the ACDNR window twice

This was easy to reproduce. 1.5.2 on Vista64.

[Nocturnal]

Hmm, maybe this was caused by the debugger being attached. I can't reproduce it in a new PI process. That's a little scary but I'm glad it's not broken.