To reproduce:

 Me.RadPanorama1.ShowGroups = True

 Dim group1 As New TileGroupElement
 group1.Text = "Group1"
 Me.RadPanorama1.Groups.Add(group1)
 group1.ColumnsCount = 3
 group1.RowsCount = 5


 group1.CellSize = New Size(200, 100)
 Me.RadPanorama1.Groups.Add(group1)
 For i = 0 To 2
     For j = 0 To 2
         Dim tile As New RadTileElement()
         tile.Row = i
         tile.Column = j
         tile.Text = "tile" & i & "." & j
         group1.Items.Add(tile)
     Next
 Next

 Dim group2 As New TileGroupElement
 group2.Text = "Group2"
 Me.RadPanorama1.Groups.Add(group2)
 group2.ColumnsCount = 3
 group2.RowsCount = 5

 Me.RadPanorama1.Groups.Add(group1)
 For i = 0 To 2
     For j = 0 To 2
         Dim tile As New RadTileElement()
         tile.Row = i
         tile.Column = j
         tile.Text = "tile" & i & "." & j
         group2.Items.Add(tile)
     Next
 Next