Long story short - just bought X7 after using X3 for quite a long time. I just noticed a difference on how the brush with low hardness work.
It wasn't obvious during photo retouching, but I started playing with basics to find out what's going on, and the result is pretty frightening.
Paint Brush, settings:
Size = 200
Hardness = 0
Step = 1
Density = 100
Thickness = 100
Rotation = 0
Opacity = 100 (thanks LindaSue for pointing out my mistake!)
Brush color = #000000
Background color = #CCCCCC
8bit pallette
Both X3 and X7 running on the same PC with Win7 Home Premium 64bit.
Reference, X3 (32bit) behaviour:

X7 (64bit) behaviour:

I got the problems also with other tools when brush hardness is set below 100.
I.e. dodge brush makes the center lighter, but corners of the brush becomes DARKER.
Any ideas what's going on?

