Zebulba said:
Almost the same but with duke titles instead, if i am duke of x beome king of y and give my duke of x title away to count of z he will be the ruler of all the counties wich dosent have a duke over them, he will even take away the counties wich is in my duchy borders
This is due to the fact that vassals will remember their liege if the title is not destroyed. I think it is the same phenomenon that causes vassals to go independent if you create them in conquered land before peace.
An example from one of my games:
I, the Duke of Flanders, managed to inherit the Duke of Lower Lorraine which transferred all his vassals to me. I then created the Duke titles of Brabant and Friesland from the newly obtained lands. Later I became King of France and wanted to create Dukes as vassals. If I create a Duke of Lower Lorraine he will get all the vassals of the Duchy before I had inherited, thus all of Friesland and Brabant. However, if I first create the Dukes of Brabant and Friesland they will get the count vassals belonging to the respective Duchies, as it should be with 1.03b. Then I can release the Duke of Lower Lorraine and he will get the remaining Dukes.
That's also what happens if you started as a Duke, become King and then give away your initial Duke title. Your new vassal will get all your former count vassal as they remember the Duke as their liege, not the new King title.