Use attached to reproduce.

Workaround
- Set the position at runtime. 
   Me.radGridView1.MasterTemplate.AddNewRowPosition = Telerik.WinControls.UI.SystemRowPosition.Bottom

To reproduce:
Public Class RadForm1
    Public RadGridView1 As RadGridView

    Private Sub RadForm1_Load(sender As Object, e As EventArgs) Handles Me.Load
        CreateGrid()
        FormatGrid()
        SetDataSource()
    End Sub

    Private Sub CreateGrid()
        Try
            RadGridView1 = New RadGridView
            Me.Controls.Add(RadGridView1)
        Catch ex As Exception
            MessageBox.Show(Me, ex.Message)
        End Try
    End Sub
    Private Sub FormatGrid()

        Dim col As GridViewTextBoxColumn
        With RadGridView1
            col = New GridViewTextBoxColumn
            With col
                .FieldName = "FieldID"
                'NOTE: Comment out NullValue = "" to prevent the unhandled exception
                .NullValue = ""
            End With
            .Columns.Add(col)
        End With
    End Sub
    Private Sub SetDataSource()
        Dim table As DataTable = Nothing
        Dim row As DataRow = Nothing
        table = New DataTable("GridList")
        table.Columns.Add("FieldID", GetType(System.Guid))
        row = table.NewRow
        row("FieldID") = Guid.Empty
        table.Rows.Add(row)
        RadGridView1.DataSource = table
    End Sub
End Class

Workaround:
Comment this line 
NullValue = ""

Use attached to reproduce.


Workaround: 

this.LoadFieldList(hiddenGrid.MasterTemplate);
this.FieldList.Add(new Telerik.Data.Expressions.ExpressionItem()
{ Name = "Test", Description = "Test", Syntax = "Test", Type = Telerik.Data.Expressions.ExpressionItemType.Field, Value = "Test" });

Use attached to reproduce.

Workaround:

DragDropService.AllowAutoScrollColumnsWhileDragging = false;
DragDropService.AllowAutoScrollRowsWhileDragging = false;

Use attached to reproduce.

Workaround:

Use CellFormatting instead of RowFormating. 

To reproduce, perform the following steps with the attached project:

Step 1: Create Sample Database
==============================
New (Sample1.db)
Import
Save
Close

Step 2:
======
Open (Sample1.db)
Import
Save
Close

Step 3:
======
New (Sample2.db)
Import (Exception)

Workaround:
 radGridView1.GridViewElement.Navigator = new MyNavigator();

class MyNavigator : BaseGridNavigator
{
    public override bool SelectLastRow()
    {
        var enumerator = typeof(BaseGridNavigator).GetField("enumerator", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(this) as GridTraverser;
        enumerator.Reset();
      
        return base.SelectLastRow();
    }
}

To reproduce:
private void radButton1_Click(object sender, EventArgs e)
{
    radGridView1.MasterView.TableSearchRow.SelectNextSearchResult();

}
Check the index in the search textbox, it is not updated. 

Workaround:
var cell = radGridView1.TableElement.FindDescendant<GridSearchCellElement>();
if (cell != null)
{
    cell.FindNextButton.PerformClick();
}

Use attached to reproduce.

With versions prior 2015.3.930 the results are different.

To reproduce:
private void RadGridView1_UserAddingRow(object sender, Telerik.WinControls.UI.GridViewRowCancelEventArgs e)
{
    radGridView1.MasterView.TableAddNewRow.CancelAddNewRow();
}
See attached video.

Workaround:
private void RadGridView1_UserAddingRow(object sender, Telerik.WinControls.UI.GridViewRowCancelEventArgs e)
{
    radGridView1.MasterView.TableAddNewRow.CancelAddNewRow();
    radGridView1.MasterView.ViewTemplate.DataView.CurrentItem.IsCurrent = false;
}

To reproduce:
Use the following code
private void RadGridView1_UserAddingRow(object sender, GridViewRowCancelEventArgs e)
{
    radGridView1.MasterView.TableAddNewRow.CancelAddNewRow();
    radGridView1.MasterView.ViewTemplate.DataView.CurrentItem.IsCurrent = false;
}

Place the new row at the bottom. While in edit mode press tab to fill until an exception is thrown.

Workaround:
BaseGridBehavior gridBehavior = radGridView1.GridBehavior as BaseGridBehavior;
gridBehavior.UnregisterBehavior(typeof(GridViewNewRowInfo));
gridBehavior.RegisterBehavior(typeof(GridViewNewRowInfo), new CustomGridRowBehavior());


internal class CustomGridRowBehavior : GridNewRowBehavior
{
    protected override bool ProcessTabKey(KeyEventArgs keys)
    {
        bool newRowIsInEditMode = this.IsInEditMode && this.GridViewElement.CurrentRow is GridViewNewRowInfo;

        if ( newRowIsInEditMode  && this.GridViewElement.Navigator.IsLastEditableColumn(this.GridViewElement.CurrentColumn))              
        {
            this.GridViewElement.Navigator.SelectFirstColumn();

            while (this.GridViewElement.CurrentColumn.ReadOnly && this.GridViewElement.Navigator.SelectNextColumn())
            { }
            return false;
        }
        return base.ProcessTabKey(keys);
    }
}

To reproduce: please refer to the attached sample project and gif file.

Workaround: add the column programmatically, not at design time.

how can i insert , update or delete? i tried after choosing the data source , it shows the data correctly but when i edit or add a new item the database is not affected (allow edit,delete and add row are set to true)

Use attached to reproduce.

Workaround:
class MySpreadExportRenderer : SpreadExportRenderer
{
    public override void SetWorksheetColumnWidth(int columnIndex, double value, bool isCustom)
    {
        if (value > 2000)
        {
            value = 2000;
        }
        base.SetWorksheetColumnWidth(columnIndex, value, isCustom);
    }
}

To reproduce:

 if (e.CellElement.ColumnInfo.HeaderText == "CategoryID")
{
     e.CellElement.DrawText = false;
}
else
{
      e.CellElement.ResetValue(LightVisualElement.DrawTextProperty, ValueResetFlags.Local);
}

Workaround:
 
e.CellElement.DrawText = true;

Use attached to reproduce!

Workaround:
remove the Begin\End update block.

Use attached to reproduce.

Workaround:
Set the TableHeaderHeight again after loading the layout. 

To reproduce:
GridViewCheckBoxColumn chkCol = new GridViewCheckBoxColumn();

chkCol.HeaderText = "I have wrap text set yet I cannot see full column header text.";
chkCol.Width = 90;
chkCol.WrapText = true;
chkCol.EnableHeaderCheckBox = true;
chkCol.EditMode = EditMode.OnValueChange;
radGridView1.Columns.Add(chkCol);

Workaround:
private void RadGridView1_ViewCellFormatting(object sender, CellFormattingEventArgs e)
{
    var cell = e.CellElement as GridCheckBoxHeaderCellElement;
    if (cell != null)
    {
        cell.CheckBox.TextWrap = true;
    }
}

How to reproduce: bind the grid using the code snippet below and enter name in the SearchRow
public partial class RadForm1 : Telerik.WinControls.UI.RadForm
{
    public RadForm1()
    {
        InitializeComponent();

        this.radGridView1.DataSource = this.GetData();
        this.radGridView1.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill;
        this.radGridView1.AllowSearchRow = true;

        this.radGridView1.MasterView.TableSearchRow.InitialSearchResultsTreshold = 0;
        this.radGridView1.MasterView.TableSearchRow.SearchResultsGroupSize = int.MaxValue;;
    }

    private DataTable GetData()
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("Id", typeof(int));
        dt.Columns.Add("Name", typeof(string));
        dt.Columns.Add("Date", typeof(DateTime));
        dt.Columns.Add("Bool", typeof(bool));
        dt.Columns.Add("Description", typeof(string));
        for (int i = 0; i < 2000; i++)
        {
            for (int j = 0; j < 5; j++)
            {
                dt.Rows.Add(i, "Name " + j, DateTime.Now.AddDays(i), i % 2 == 0 , "Description " + i);
            }
        }

        return dt;
    }
}

Workaround: in the search row, set the InitialSearchResultsTreshold property to 0 and the SearchResultsGroupSize property to int.MaxValue
public RadForm1()
{
    InitializeComponent();

    this.radGridView1.DataSource = this.GetData();
    this.radGridView1.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill;
    this.radGridView1.AllowSearchRow = true;

    this.radGridView1.MasterView.TableSearchRow.SearchProgressChanged += TableSearchRow_SearchProgressChanged;
    this.radGridView1.MasterView.TableSearchRow.InitialSearchResultsTreshold = 0;
    this.radGridView1.MasterView.TableSearchRow.SearchResultsGroupSize = int.MaxValue;
}