By default, the ribbon will automatically collapsed when the container is less than 300 pixels wide when the UltraToolbarsManager.DockWithinContainer is a form otherwise it will default to 0 (i.e. it will not automatically collapse).
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