Cannot set a custom colour for the launcher

[fossfreedom]

unity-tweak-tool version 0.04 - raring (13.04)

following error seen when setting the launcher custom colour:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/UnityTweakTool/elements/colorchooser.py", line 102, in handler
    value=self.get_color()
  File "/usr/lib/python3/dist-packages/UnityTweakTool/elements/colorchooser.py", line 89, in get_color
    self.ui.get_rgba(self.color)
  File "/usr/lib/python3/dist-packages/gi/types.py", line 113, in function
    return info.invoke(*args, **kwargs)
TypeError: get_rgba() takes exactly 1 argument (2 given)

The colour of the launcher does not take effect until you click back to "Colour based on wallpaper" and then back to "custom"