To reproduce: please refer to the attached gif file demonstrating how to replicate the problem with the Demo application. Scroll with the mouse wheel and you will notice the the row index disappears until you click a cell. Using the thumb will behave as expected. 

Workaround:
this.radSpreadsheet1.SpreadsheetElement.VerticalScrollBar.ValueChanged+=VerticalScrollBar_ValueChanged;
        private void VerticalScrollBar_ValueChanged(object sender, EventArgs e)
        {
            this.radSpreadsheet1.SpreadsheetElement.InvalidateMeasure(true);
        }

RadSpreadsheet must support printing using RadPrintDocument. 

Set the Print Area as described here: https://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/worksheetpagesetup

This is possible in WPF

Workaround: create a custom input behavior class and manually handle the navigation when holding the Shift key
public partial class SpreadsheetForm : Telerik.WinControls.UI.RadForm
{
    public SpreadsheetForm()
    {
        InitializeComponent();

        FieldInfo behaviorFi = typeof(RadSpreadsheetElement).GetField("inputHandler", BindingFlags.Instance | BindingFlags.NonPublic);
        behaviorFi.SetValue(this.radSpreadsheet1.SpreadsheetElement, new CustomSpreadsheetInputBehavior(this.radSpreadsheet1.SpreadsheetElement));
    }
}

public class CustomSpreadsheetInputBehavior : SpreadsheetInputBehavior
{
    public CustomSpreadsheetInputBehavior(RadSpreadsheetElement element)
    : base(element) { }

    public override void ProcessKeyDown(KeyEventArgs e)
    {
        base.ProcessKeyDown(e);

        if (e.Shift)
        {
            switch (e.KeyCode)
            {
                case Keys.Left:
                    this.Spreadsheet.ActiveWorksheetEditor.Commands.UpdateActiveSelectionRangeCommand.Execute(MovementType.MoveToPreviousColumn);
                    break;
                case Keys.Up:
                    this.Spreadsheet.ActiveWorksheetEditor.Commands.UpdateActiveSelectionRangeCommand.Execute(MovementType.MoveToPreviousRow);
                    break;
                case Keys.Right:
                    this.Spreadsheet.ActiveWorksheetEditor.Commands.UpdateActiveSelectionRangeCommand.Execute(MovementType.MoveToNextColumn);
                    break;
                case Keys.Down:
                    this.Spreadsheet.ActiveWorksheetEditor.Commands.UpdateActiveSelectionRangeCommand.Execute(MovementType.MoveToNextRow);
                    break;
            }
        }
    }
}

The control can be resized in the designer.  The resize operation starts with a slight delay and it is necessary to wait for this initial delay. From then on the control can be freely resized. The attached gif file illustrates this.

Workaround:
1. Set the size using the property grid
2. Add a panel and dock the control to fill the panel, then resize the panel

How to reproduce: check the attached project and the remaining memory after disposing the forms.