Activate

Activate

Dim objRibbonTab As Microsoft.Office.Tools.Ribbon.RibbonTab 
objRibbon.Activate 

ActivateTab

ribbon.ActivateTab "TabAddIns"; 

ActivateTabMso

this.RibbonUI.ActivateTabMso("TabAddIns"); 

ActivateTabQ

ribbon.ActivateTabQ - this is used for tabs shared between multiple add-ins 

This also requires an additional string parameter that specifies the namespace of the add-in