JFreeChartEngine lines 1860-1897
DialModel.getFrameBgRGB is used twice
1. as the frameBGcolor surrounding the the dial,
2. and the gradient start color of the dial background
DialModel.getFrameBgRGB1 is never used
DialModel.getFrameBgRGB2 is used as the gradient end color of the dial background
like that it is not possible to give the border of the chart a different color than its gradient start color...
in DialModel there is no way to customize the color of the numbers in the Scale are always blue
JFreeChartEngine should also apply the color retrieved by DialModelScale.getTickRGB() in line 1960 to dscale.setTickLabelPaint(Color)
in addition DialModelScale.getTickFont() is never used ...