I think that if you want to put the label to the left side of the circle button, then you should read the documentation found at the index entry "controls > customizing".

Also the section "Building Custom Control UIs". Here is some of the advice from that section:

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If you need a different visual appearance for the control for the same situations, but want to implement it beyond the label or you want to set properties that affect appearance in those situations, then

Define a UI class and a control class that uses it.

• In your UI class, implement the draw-as-* methods you need. Also ensure that the constructor takes a control= keyword argument and passes it to the superclass's constructor.

• In the simple control class, implement create-default-ui-object to return a new instance of the UI object with control=self.

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But maybe you would only have to subclass and override the StandardRadioButtonUI.draw-label method.

You might also look at the open source for the controls which comes with the IDE in the ide/gui/controls directory. Look at the documentation chapter that you can find by looking at the index entry for "controls > open".