Slightly confused with setFillGray

Hi all

This is a minor point, but I want to make sure I understand it.

I thought that setFillGray(0), setFillColorRGB(0, 0 ,0), and 
setFillColor(colors.black) were interchangeable.

I have discovered that, if you have previously executed 
setFillColor(colors.transparent), alpha is set to 0.

If you then execute any of the above commands, only 
setFillColor(colors.black) resets the alpha value. The other two do not, 
resulting in text being invisible.

Am I missing something?

Frank Millman