Everyone is correct but here is the problem sks 5 &6 both make back up files
So disable the feature in 6 HideShadows=0
save and apply
Now go to the windowblinds folder for this skin open the folder (set veiw to thumbnails)you will find a file called XPStuff.xp(it will have a skinstudio icon)
this is your good file
now you will find another file XPStuff.xp~ (it will look just like a normal file folder the squiggley line denotes a copy)
now delete the XPStuff.xp~
now open in SKS5 and enable(HideShadows=1)
save and apply
it will be gone ,open in SKS6 and continue building
Note when you start a skin if you start in 5 make this your first change save and apply then open in 6 you wont have this problem again!
It can be done in note pad but I recomend this way unless you are comfortale directly editing code!
Note there could be more than 1 backup of this file if so delete all XPStuff.xp~ (it will look just like a normal file folder the squiggley line denotes a copy)
you only need the 1 with the SKS icon w/o the squiggley line
This will work I am sure !