Your layout is wrong. You are not using anchors correctly.
You should watch the visual designer tutorial:
The mail panel in your layout should be anchored to the top and left and you should load it like this:
B4X:
Private Sub Application_Start (Nav As NavigationController)
NavControl = Nav
Page1.Initialize("Page1")
Page1.Title = "Page 1"
Page1.RootPanel.LoadLayout("mainreports")
Page1.RootPanel.Color = Colors.White
NavControl.ShowPage(Page1)
Dim p As B4XView = Xui.CreatePanel("")
p.SetLayoutAnimated (0, 0, 0, 960dip, 2216dip)
p.LoadLayout("reports")
ScrollViewMain.Add(p, "")
End Sub
Private Sub Page1_Resize(Width As Int, Height As Int)
End Sub
For this to work properly you need to fix the reports layout. Don't use %y at all. Start with removing all the designer script code.