In this code I have a grid with a second grid in it (Grid1).
  When an object is added to Grid1 a corresponding button is created in the stack panel below.
  Which object is displayed in Grid1 is chosen by clicking the appropriate button.
  All good BUT I can not work out how to set the colour of the button in the Button Click Event (btnAddPO_Click or btnAddGR_Click) at present I set the colour to Yellow in the function but this means that all buttons in the stack panel are all the same colour. I wish to set the colour in the btnAddPO_Click or btnAddGR_Click events then past it to the function. 
  Any Ideas ?
  I have attached the full code.
   
  Thank you Tony.