InfoPath Dev

When I run my form and select items from the multiple selection listboxes, I show null items in the saved xml:

<my:LegMarkings>
    <my:LegMarking xsi:nil="true"></my:LegMarking>
   <my:LegMarking>1</my:LegMarking>
   <my:LegMarking>2</my:LegMarking>
</my:LegMarkings>
<my:BodyMarkings>
    <my:BodyMarking xsi:nil="true"></my:BodyMarking>
   <my:BodyMarking>6</my:BodyMarking>
</my:BodyMarkings>

I don't see any blank entries in the lists or in the datasource so I am wondering where the "nil=true" nodes are coming from. Any ideas where I might look?

In 2010, go to Data tab -> Default Values -> uncheck the field that MSLB control is bound to.  That should get rid of your null value.

Thanks Anson. I tried these but it seemed to break the rules I have to show and hide the MSLB. I ended up writing some code:

 

                XPathNavigator nav = CreateNavigator().SelectSingleNode("/dfs:myFields/my:Markings/my:BodyMarkings/my:BodyMarking", NamespaceManager);
                if (nav.InnerXml == "")
                    CreateNavigator().SelectSingleNode("/dfs:myFields/my:Markings/my:BodyMarkings/my:BodyMarking", NamespaceManager).DeleteSelf();
                nav = CreateNavigator().SelectSingleNode("/dfs:myFields/my:Markings/my:LegMarkings/my:LegMarking", NamespaceManager);
                if (nav.InnerXml == "")
                    CreateNavigator().SelectSingleNode("/dfs:myFields/my:Markings/my:LegMarkings/my:LegMarking", NamespaceManager).DeleteSelf();