Interestingly the v2_2 was different and string-Properties were shown in black color. That's what I wanted when I used the PropertyGrid as "ReadOnly". Maybe it is a philosophical question how it should behave. I looked for a way just to show the user some data (that he can't modify) but not in a greyed-out style.
I will have a look at modification of the base styles of the controls.
I will have a look at modification of the base styles of the controls.