By default tools within a ribbongroup are made as large as they are allowed to be and then shrunk down when there is no enough room based on the default variants for the groups (and in the absence of any variants based on the default resizing). The min and max sizes of tools on a ribbon group are controlled by the attached properties defined by RibbonGroup - MaximumSize and MinimumSize. Since ButtonTools are commonly small within Office apps it was decided that the default MaximumSize for a ButtonTool would be ImageAndTextNormal. If you would like a specific buttontool to be large then you can set its MaximumSize to ImageAndTextLarge either via xaml (e.g. igRibbon:RibbonGroup.MaximumSize = "ImageAndTextLarge") or in code using the RibbonGroup.SetMaximumSize method.