Try it:

1) Create class (GRID)
Change the values of HighlightBackColor and HighlightForeColor.
Save this class.

2) Create a form.
Put this class in it.
Check the values of HighlightBackColor and HighlightForeColor. It is wrong.
So, change the value for another one...
Then RightClick and "Reset as default"... The value is right now...
Save the form.
Open the form again... Check the values... It is wrong!

I check these two properties, but I think there is more with the same problem.

[]s!