RadMultiColumnComboBox provides support for right-to-left presentation.
    
    
        RadMultiColumnComboBox considers the direction attribute set to the control itself or any parent
        HTML element. If you set the direction of the body tag (or any other parent element
        that contains the control) to rtl, RadMultiColumnComboBox reverses the
        position of the button and aligns the text to the right side of the container.
    
    
<telerik:RadMultiColumnComboBox ID="RadMultiColumnComboBox1" runat="server" dir="rtl" ... />