Just a thought: once a user clicks on some radio button, it'll be selected, but the user will have no standard way to remove/undo this selection. The only possibility is to switch to another radio button on the same radio button group. As far as I know*, this behavior occurs on all popular GUIs, including web, windows forms, qt and gtk, and probably others.
It's been like that for so many years, isn't it time to add a "deselect radio button" standard? Just like a checkbox, a single click would be a simple enough way to undo a selection. For special cases, a "ForceSelection" property may indicate that this radio button group cannot be deselected, to preserve the current behavior.
* I merely researched this topic, it's a just-a-thought kind of post and might be inaccurate.