How to have only 2 RibbonRadioButton?

The RibbonGroup needs 3 RibbonRadioButton for the next (4th) Control to be placed on the next right column. If I have only 2 RibbonRadio开发者_如何转开发Button and the next Control is a TextBox, the TextBox would appear underneath the 2 RibbonRadioButton.

How can I have fewer than 3 RibbonRadioButton by itself in one column?

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I think that

<StackPanel Orientation="Horizontal">
    <Item1 />
    <Item2 />
    <Item3 />
</StackPanel>

is what you need. Also you can try to play with width.