yardenasky

Ahhh got it. Thanks for the info!

He mentioned that the histogram being grey was a bug. I wasn't sure if that was the same issue causing the curves master to look averaged.

That's what it looks like. Is this a bug? It only happens on my dad's PC. I've never had this issue on my Mac.

Well at least I can tell my dad that the grey bit isn't an issue. As for the two curves adjustments, I just had him pull up a second one to illustrate the point. The same thing happens even on a brand new image with no other adjustments. It's like the curves graph only shows part of the full histogram.

My dad just downloaded the newest version of Photo for Windows. When he tries to add a curves adjustment, the histogram is greyed out and doesn't match the curves in the main histogram panel. Individual color channels show the correct graph (albeit greyed out), but when he chooses the master channel, the graph is wrong. This happens on all new documents. I've attached a screenshot of the curves adjustment panel next to the histogram panel to show the difference.