Workaround: Handle the MouseWheel event of the control

private void RadSpreadsheet1_MouseWheel(object sender, MouseEventArgs e)
{
    int offset = this.radSpreadsheet1.SpreadsheetElement.VerticalScrollBar.SmallChange * 3;
    int x = e.Delta < 0 ? offset : -offset;
    this.radSpreadsheet1.SpreadsheetElement.VerticalScrollBar.ClampValue = true;
    this.radSpreadsheet1.SpreadsheetElement.VerticalScrollBar.Value += x;

    RadWorksheetEditor editor = this.radSpreadsheet1.SpreadsheetElement.ActiveSheetEditor as RadWorksheetEditor;
    if (editor != null)
    {
        IRadWorksheetEditorPresenter presenter = (IRadWorksheetEditorPresenter)editor.GetType().GetField("activePresenter", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic).GetValue(editor);
        presenter.SetVerticalOffset(presenter.VerticalOffset + x);
        editor.InvalidateMeasure(true);
    }
}

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.

To reproduce:
- Open the first look example. 
- Choose Save from the backstage button.
- Currently, the default is PDF, It should be xlsx.