A RibbonGroup can become collapsed when there is not enough room to display the contents of the RibbonGroup within the containing RibbonTabItem and the RibbonGroup is allowed to be collapsed. A RibbonGroup indicates that it is allowed to be collapsed if it contains a GroupVariant in its Variants collection that has a resize action of CollapseRibbonGroup or if all RibbonGroups within the owning RibbonTabItem have no GroupVariants defined, in which case the default resizing logic will be used which includes allowing the RibbonGroup to be collapsed.
Note: A RibbonGroup may only be collapsed when it is within a RibbonTabItem. A RibbonGroup displayed within the QuickAccessToolbar is not considered to be collapsed and therefore this property will return false for the RibbonGroup.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, 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