'just a not working example :)
Private Sub PanMenu_MouseEntered (EventData As MouseEvent)
panMenu.Width = 200 'this is read only
panContent.Left = panMenu.Width
panContent.Width = B4XPages.GetNativeParent(Me).Width - panContent.Left
End Sub
Private Sub PanMenu_MouseExited (EventData As MouseEvent)
panMenu.Width = 60 'this is read only
panContent.Left = panMenu.Width
panContent.Width = B4XPages.GetNativeParent(Me).Width - panContent.Left
End Sub