This is done in your Config.esriaddin file (XML)in your Menu >> items.This is not showing the entire XML file but shows you where the 'separation' comes into play.When set to true... the space if in the toolbar, will appear BEFORE the tool. If in a menu, will appear above. <Toolbars> <Toolbar id="CompanyToolsToolbar" caption="Our Company Toolbar ©2012 v11.1" showInitially="true"> <Items> <!--Reference to the custom menu to provide access to the custom multiItem --> <Menu refID="CompanyToolsToolbar_Addin_v10_SomeMenu" separator="false"/> <!--Reference to the custom menu to provide access to the custom multiItem --> <Menu refID="CompanyToolsToolbar_Addin_v10_DataCreateMenu" separator="false"/> <!--Reference to the custom menu to provide access to the custom multiItem --> <Menu refID="CompanyToolsToolbar_Addin_v10_DistancesMenu" separator="false"/> <!--Reference to the custom menu to provide access to the custom multiItem --> <Menu refID="CompanyToolsToolbar_Addin_v10_ConverterMenu" separator="false"/> <!--Reference to the custom menu to provide access to the custom multiItem --> <Menu refID="CompanyToolsToolbar_Addin_v10_TableDatasetMenu" separator="false"/> <!--Reference to the custom menu to provide access to the custom multiItem --> <Menu refID="CompanyToolsToolbar_Addin_v10_CoordinatesMenu" separator="false"/> <!--BUTTONS--> <!--Reference to the custom button and tool--> <Button refID="CompanyToolsToolbar_Addin_v10_MapLayoutSpelling" separator="true"/> <!--Reference to the custom button and tool--> <Button refID="CompanyToolsToolbar_Addin_v10_ProjectTracker" separator="true"/> </Items> </Toolbar> </Toolbars> </ArcMap> </AddIn>