Using a Palette to change DzWidget colours

Using a Palette to change DzWidet colours has anyone made this work and have some code examples to show.

var oMyNewGB = new DzGroupBox();

oMyNewGB.paletteBackgroundColor.setRgb( 0,0,0 ); // does nothing
oMyNewGB.paletteBackgroundPixmap = new Pixmap( pathToImage ); // does nothing
oMyNewGB.palette.window = new Color( 0,0,0 ); // does nothing
oMyNewGB.palette.active.window = new Color( 0,0,0 ); // also does nothing
oMyNewGB.palette.active.window.setRgb( 0,0,0 ); // alas also does nothing

oMyNewGB.palette.window.value // returns the number 95
oMyNewGB.palette.window.value = 100; // does nothing - value is still 95 

So my question is - what is the magic sauce for actually changing the colour of interface widgets in script?