This doesn’t appear to be an NLP issue. The Windows system treats NLP as part of LrC, and to highlight the currently active NLP window in the foreground, it dims LrC. As a result, previewing and editing negatives becomes impossible.
I wonder if you might have something in your Windows settings that is causing this or may have a specific program that is doing this. For instance, I know on Mac I have a program called HazeOver that causes this effect if I have Haze Over activated. Maybe other Windows users could chime in and let us know if they’re experiencing the same thing.
Also, it would be great to know exactly what version of Windows you are using as it may be isolated to specific versions.
I also believe that something in my Windows settings is causing this. But due to my academic commitments, I haven’t got time to do film photography since March and haven’t been using NLP in this period. There were multiple Windows updates during this time, and I also applied quite a few modifications to my system. It’s almost impossible to pinpoint exactly which change caused the problem.
Thankfully after repairing my Windows 11 system using the MediaCreationToolW11, the issue has disappeared for now. Although I haven’t found the root cause, at least it’s resolved.
BTW, my current system version is Windows 11 Pro 24H2, build 26120.5722.