Vector object height weirdness

Can anyone tell me why increasing or decreasing the height parameter of a vector object appears to scale the display object?

local bar = display.newRect( 20, display.contentHeight-60, 20, 10 )   
bar:setFillColor(255,0,0)  
bar.height = 50  

Thanks! [import]uid: 10332 topic_id: 3759 reply_id: 303759[/import]