Why scrollview does'nt scroll?

Bonjour
I have a scrollview "scrollview1" put witth the designer in a file "memobs.bal"
I use a tableHost : TabHost1.AddTab("T21", "memobs")

Sub Activity_Create(FirstTime As Boolean)
Activity.LoadLayout("Main")

TabHost1.AddTab("T21", "memobs")
TabHost1.AddTab("T21", "t21")
TabHost1.AddTab("ACM", "page3")

scrollview1.panel.Color=Colors.DarkGray
scrollview1.Panel.Height = 400

'Début de grossesse
DgLbl.Initialize("")
scrollview1.Panel.AddView(DgLbl,5,5,45%x,22)
'Terme de grossesse
TermeLbl.Initialize("")
scrollview1.Panel.AddView(TermeLbl,160,5,45%x,22)
'Echographies
EchosLbl.Initialize("")
scrollview1.Panel.AddView(EchosLbl,0,30,93%x,60)
'HT21
HT21Lbl.Initialize("")
scrollview1.Panel.AddView(HT21Lbl,0,95,93%x,70)
'Conges
CongesLbl.Initialize("")
scrollview1.Panel.AddView(CongesLbl,0,170,93%x,40)
'Examens
ExamsLbl.Initialize("")
scrollview1.Panel.AddView(ExamsLbl,0,215,93%x,70)
'Anesthesistes
AnesthLbl.Initialize("")
scrollview1.Panel.AddView(AnesthLbl,0,290,93%x,40)
End Sub

All is displayed correctly when I run but it does'nt scroll, all is fixed. What is missing?
Thank you very much