Im fixing some issues in the TFS plugin and am having problems with the f:dropdownList. When the data is submitted to the SCMs descriptor into the configure(StaplerReques, JSONObject) method the name for the list is empty. By looking at the JSON data I can see that the list result exists but the key is empty.

Ive cleaned up my global.jelly file so it only looks like this:
<j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
<f:section title="Team Foundation Server">
<f:dropdownList name="fruit" title="Fruits">
<f:dropdownListBlock title="a" value="A"/>
<f:dropdownListBlock title="b" value="B"/>
</f:dropdownList>
</f:section>
</j:jelly>

And my configure() method looks like this:
@Override
public boolean configure(StaplerRequest req, JSONObject formData) throws FormException

{ System.out.println(formData); System.out.println("fruit=" + req.getParameter("fruit")); save(); return true; }

And this is what it outputs:

{"":"B"}

fruit=null