#expected result:
The toBack and toFront functions work properly.
#Actual result:
The fourth case can't load image and others work normally.
 

#Steps to reproduce:
1)Open the graphics/api/node/toBacktoFront.fx.
2)Each time user presses on the "left" key the Node on the top of RED rectangle is
 brought to back and Node hidden from the user by rectangle is brought to front.
3)User should confirm the Nodes:TextBox,ImageView,MediaView,Group(Circle,Text),Text,Circle
and Path coule be sent to Front and Back.
 You will notice thise issue.