The DialogBoxLauncherKey is used by the group to find the button tool that should be associated with the dialog box launcher displayed within the group's caption area. If this property is left to an empty string, which is the default value, an dialog box launcher will not be displayed within the group caption. The ButtonTool must be part of the associated UltraToolbarsManager.Tools collection.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2