Well.
It was more easy to make a little fix in jdom radio than to have a long explanation.
Regenerate your component and if you are already in production, only overwite JDom
(or only html/form/input/radio.php)
Maybe you don't have this file. No panic. To get this JDom class, your project MUST contain at least 1 boolean PRESENT in a at least 1 layout.
In the template, in your code :
<?php echo JDom::_('html.form.input.select', array(...
Change to :
<?php echo JDom::_('html.form.input.radio', array(...
This is the power of JDom !
JDom has not been created for incredible controls, but ONLY to be able to abtract the HTML controls.
This works also in the filters as well.
JDom has to progress even more.
If you like the concept and understand the framework, you can propose me your controls.