splitButton

In the object model this is RibbonSplitButton.
combines a button and a menu
you can either click the button or click on the menu
This is similar to the menu control in that it can include other controls
A SplitButton can be clicked directly and pushed as a button or its dropdown list can be displayed
It can also be configured to act list a togglebutton and have a toggled checked or unchecked state
Unlike the menu control the items cannot be changed dynamically at runtime
The buttons element cannot include a "size" attribute when they are inside a splitbutton.

<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui"> 
  <ribbon startFromScratch="true">  
    <tabs> 
      <tab id="CustomTab" label="My Tab"> 
        <group id="Group1" label="Group 1"> 
          <splitButton id="MySplitButton1" 
                       size="large"> 
            <button id="Button1" 
                    label="Normal Button with Menu" 
                    imageMso="LeaveReader" /> 
            <menu id="Menu1" 
                  itemSize="normal" > 
              <button id="Button2" label="First" /> 
              <button id="Button3" label="Second" /> 
              <button id="Button4" label="Third" /> 
            </menu> 
          </splitButton> 
          <splitButton id="MySplitButton2" 
                       size="large"> 
            <button id="Button5" 
                    label="Large Button with Menu" 
                    imageMso="LeaveReader" /> 
            <menu id="Menu2" 
                  itemSize="normal" > 
              <button id="Button6" label="First" /> 
              <button id="Button7" label="Second" /> 
              <button id="Button8" label="Third" /> 
            </menu> 
          </splitButton> 
        </group> 
      </tab> 
    </tabs> 
  </ribbon> 
</customUI> 

Attributes (properties)

Children

This control can contain the following controls

C# Events (design-time)

The splitButton control has a Click event which can be accessed from the Visual Studio Ribbon Designer.
This event is the design-time equivalent of the Click event for its corresponding button.

Callbacks (run-time)