Yes indeed by default the maximum number of shapes which are previewed when moved is 20. You can control this settings from the MaxPreviewedItems property of the drawing settings:
// increase max previewed items
drawingView.Drawing.Settings.MaxPreviewedItems = 30;
The drawing settings object also contains other settings related to drawing editing, such as the offset at which shapes are pasted, nudge tool step and other that are useful for the user.
Nevron Support Team