change colour of datagrid button

I have a datagrid where the last column is a button. By default I want this button to be green with a tick character and then change to red with a cross when pushed. The tick and the cross, no problem but I cannot find a way of changing the button colour, only the background colour of the cell. I have tried using flat or popup which would be OK if it weren't for the annoying button that pops up especially when you have a wingding2 tick which shows as P.
Does anyone know how to change the colour of the button or failing that stop the other button popping up. I am guessing as the pop up button disappears after a short time this could possibly be reduced to zero. Any help would be appreciated.