Background optimization
There is a hidden assumption that the background behind the ListView is solid black. If you set the background to something else like a gradient background or image you will see that during scrolling the background disappears.
You can change the background scrolling color with the ScrollingBackgroundColor property. If the background is not solid color set it to Colors.Transparent.
Example (the activity background is a gradient):
Dim GD As GradientDrawable
GD.Initialize("TR_BL", Array As Int(Colors.Gray, Colors.LightGray))
Activity.Background = GD
ListView1.ScrollingBackgroundColor = Colors.Transparent
Tips
If you want a single line item with a bitmap (and do not need two lines and a bitmap), you can set the visible property of the second label to false.