great! thanks for the help, I now realize what i did wrong.
it now works, like i needed it.
<CommandMethod("DOCRIB")> _
Public Sub DOCRIBCMD()
Dim ribCntrl As Autodesk.Windows.RibbonControl = Autodesk.AutoCAD.Ribbon.RibbonServices.RibbonPaletteSet.RibbonControl
Dim flag As Boolean = False
For Each tab As RibbonTab In ribbonCtrl.Tabs
If tab.Id.ToUpper() = "DOCTAB" Then
tab.IsActive = True
flag = True
_ed.WriteMessage("Tab already added")
End If
Next
If flag = False Then
Dim ribbon As New RIBBON()
ribbon.Register()
_ed.WriteMessage("Tab added")
End If
End Sub