Eclipse Does Not Recognize GWT UiBinder RadioButton

Eclipse/UiBinder won't recognize RadioButton, and I feel like I have tried everything to get it to work.

I have added the import at the top, that isn't recognized(even though RadioButton should be in the client UI bundle, that is imported by default as far as I can tell, and I have tried writing the tag in every conceivable way, but Eclipse still says:

Attribute RadioButton has no value.

The thing that really gets me is that I added the UiField in the Java parent file, and it imported just fine. I'm about to de-evolve into an ancestor made of pure anger as the project hinges on me figuring this out.

I appreciate any help that may be given. Here is my code:

DOCTYPE ui:UiBinder SYSTEM "http://dl.google.com/gwt/DTD/xhtml.ent"
ui:UiBinder xmlns:ui="urn:ui:com.google.gwt.uibinder"
xmlns:g="urn:import:com.google.gwt.user.client.ui"
xmlns:gwt="urn:import:com.google.gwt.user.client.ui.RadioButton"

<g:HTMLPanel>

    <g:Label ui:field="label">Starting Text</g:Label>

    <g:VerticalPanel>
        <gwt: RadioButton ui:field="radio2" ui:name="radio">Option2</gwt:RadioButton>
        <g: RadioButton ui:field="radio3" value="value1" name="radio">Option3</g:>
        <gwt: RadioButton ui:field="radio4" name="radio"/>
        <ui: RadioButton ui:field="radio5" name="radio">Option5</ui:>
    </g:VerticalPanel>

</g:HTMLPanel>

The correct way to use RadioButton is this:

<g:RadioButton ui:field="radio" name="radio">Option 1</g:RadioButton>

The reason for the error, by the way, is the space before RadioButton. It makes it an attribute instead of a part of a tag.