[farshizzo]

You can customize the global theme to change the colors of all GUI objects. If you just want to change the color of a single textbox, then you can use the following code:

textbox.color(viz.RED,viz.TEXTBOX_BORDER) # red border
textbox.color(viz.WHITE,viz.TEXTBOX_BACK) # white background
textbox.color(viz.BLACK,viz.TEXTBOX_TEXT) # black text