i want to Creates a new view (tab) in the FeatureManager design tree,use the commend: 

swFeatMgrTabBtm = swModViewMgr.CreateFeatureMgrControl2(iconSmall, "MSCAL.Calendar", "", "Tab ToolTip", swFeatMgrPane_e.swFeatMgrPaneBottom)

in the FeatureManager design tree,the bitmap can be shown,but the value of swFeatMgrTabBtm is nothing,and there is nothing in the new featuremanager design tree,

i don't know where the problem is?   SOS!!!