The effect I wanted is (as you wrote in #9)
	
	
	
	
	
	
	
	
	
		Panel2t.SetTopAndBottom(0,Panel2.Height)
	 
	
	
		
	
 In my example the same is achieved with
	
	
	
	
	
	
	
	
	
		Panel2t.SetTopAndBottom(0%y,50%y)
	 
	
	
		
	
 what is really strange and leads me to this conclusion:
setTopAndBottom actually refers to the activity (as you allways sayed). Lets say: a size is produced, using activity-measures. 
But then this size is transferred into panel2.(and that all happens in designer). This is the only way all that makes sense for me.
So y%0 later refers to y0 in panel2 and
 SetTopAndBottom does not scale the view within panel2.
Ush, this was a hard nut to crack for me!
Thank you ALL, I hope it all works the way it appears to me now!!