To reproduce:
Add a TabControl and two tabs. In the second tab add a RadGridView and in the Load event of the form set the SplitMode property of the grid. You will notice that it will not have effect until grouping or other similar action has been performed.

Workaround:
private void Form1_Load(object sender, EventArgs e)
{
    DataTable dt = new DataTable();
    dt.Columns.Add("column1");
    dt.Columns.Add("column2");

    RadGridView1.DataSource = dt;

    this.RadGridView1.VisibleChanged += Visible_Changed;

}

private void Visible_Changed(object sender, EventArgs e)
{
    if (this.RadGridView1.Visible & !this.RadGridView1.SplitMode.Equals(Telerik.WinControls.UI.RadGridViewSplitMode.Horizontal)) {
        RadGridView1.SplitMode = Telerik.WinControls.UI.RadGridViewSplitMode.Horizontal;
    }
}

To reproduce:
Add a RadGridView and use the following code to populate it:
for (int i = 0; i < 15; i++)
{
    this.grid.Columns.Add(string.Format("Column {0}", i));
}

for (int i = 0; i < this.grid.Columns.Count * 15; i++)
{
    this.grid.Rows.AddNew();
}t
Set the theme to TelerikMetroTouch.
Scroll somewhere below the middle leave the scrollbar and leave the grid with the mouse. You will notice that the value of the scrollbar will change.

Workaround:
Subscribe to the RadPropertyChanging event of the TableElement:
RadGridView1.TableElement.RadPropertyChanging += Property_Changing;

void TableElement_RadPropertyChanging(object sender, RadPropertyChangingEventArgs args)
{
    args.Cancel = args.Property == GridTableElement.RowHeightProperty ||
                    args.Property == GridTableElement.TableHeaderHeightProperty ||
                    args.Property == GridTableElement.GroupHeaderHeightProperty ||
                    args.Property == GridTableElement.FilterRowHeightProperty;
}

To reproduce
- add Calculator column in the grid
- set the EnterKeyMode to EnterMovesToNextRow
- press enter when the cell is in edit mode.

Workaround:

-use custom GridDataRowBehavior like this:

class MyNewEnterBehavior : GridDataRowBehavior
{
    bool firstTime = true;
    protected override bool ProcessEnterKey(KeyEventArgs keys)
    {
        if (this.GridControl.IsInEditMode && this.GridControl.CurrentColumn is GridViewCalculatorColumn )
        {

            if (firstTime)
            {
                firstTime = false;
                return false;
            }
            firstTime = true;
            return base.ProcessEnterKey(keys); 
        }
        return base.ProcessEnterKey(keys);
    } 
}

In RadGridView with a TextBoxColumn.
  Set WrapText, Multiline and AcceptsReturn to true
  If  adding a new line, the return gives another new line instead of staying within the cell.

Workaround:
  Create a new behavior class:
//VB
Class MyNewRowBehavior
    Inherits GridNewRowBehavior
    Protected Overrides Function ProcessEnterKey(keys As KeyEventArgs) As Boolean
        If Me.GridControl.IsInEditMode AndAlso Me.GridControl.CurrentColumn.Name = "TextBoxColumn" Then
            Dim editor As RadTextBoxEditor = TryCast(Me.GridControl.ActiveEditor, RadTextBoxEditor)
            Dim element As RadTextBoxEditorElement = DirectCast(editor.EditorElement, RadTextBoxEditorElement)

            element.Text.Insert(element.Text.Length, Environment.NewLine)
            Return True
        Else
            Return MyBase.ProcessEnterKey(keys)
        End If
    End Function
End Class

//C#
class MyNewRowBehavior : GridNewRowBehavior
{
    protected override bool ProcessEnterKey(KeyEventArgs keys)
    {
        if (this.GridControl.IsInEditMode && this.GridControl.CurrentColumn.Name == "TextBoxColumn")
        {
            RadTextBoxEditor editor = this.GridControl.ActiveEditor as RadTextBoxEditor;
            RadTextBoxEditorElement element = (RadTextBoxEditorElement)editor.EditorElement;

            element.Text.Insert(element.Text.Length, Environment.NewLine);
            return true;
        }
        else
        {
            return base.ProcessEnterKey(keys);
        }
    }
}

then unregister the old behavior and register the new one:
//VB
DirectCast(radGridView1.GridBehavior, BaseGridBehavior).UnregisterBehavior(GetType(GridViewNewRowInfo))
DirectCast(radGridView1.GridBehavior, BaseGridBehavior).RegisterBehavior(GetType(GridViewNewRowInfo), New MyNewRowBehavior())

//C#
((BaseGridBehavior)radGridView1.GridBehavior).UnregisterBehavior(typeof(GridViewNewRowInfo));
((BaseGridBehavior)radGridView1.GridBehavior).RegisterBehavior(typeof(GridViewNewRowInfo), new MyNewRowBehavior());

Steps to reproduce:
1) Add RadGridView control
2) Use GridViewDecimalColumn:

        DataTable customDataTable = new DataTable();
        sampleDataTable.Columns.Add("Column name", typeof(double));

3) Set the right-to-left property of the control to true:

        this.radGridView1.RightToLeft = System.Windows.Forms.RightToLeft.Yes;

4) Re-size the form manually until horizontal scroll-bar appears and you will notice that the left border is missing

Expected result: the left border of the GridRowHeaderCellElement is visible
Actual result: the left border of the GridRowHeaderCellElement is missing

Workaround:
this.radGridView1.ViewCellFormatting +=new CellFormattingEventHandler(radGridView1_ViewCellFormatting);
 
void radGridView1_ViewCellFormatting(object sender, CellFormattingEventArgs e)
{
    if (e.CellElement is GridRowHeaderCellElement)
    {
        e.CellElement.BorderLeftWidth = 3;
    }
}

To reproduce:

Add a RadGridView to a form, dont dock it. Use the following code to add the rows, columns and the definition:



this.Grid.Columns.Add("Old");
this.Grid.Columns.Add("New");

Start the application and you will see that you cannot scroll to the end, horizontally.



Workaround:

Use the following code on a button click or execute it in a timer a few millisecond after the form has loaded in order to update the scrollbar's maximum value accordingly:



int width = 0;
foreach (var col in this.Grid.Columns)
{
    width += col.Width;
}


this.Grid.TableElement.HScrollBar.Maximum = width - this.Grid.TableElement.HScrollBar.SmallChange - this.Grid.TableElement.RowHeaderColumnWidth;

How to reproduce: 
Public Class Form1
    Sub New()

        InitializeComponent()

        Dim col As New GridViewTextBoxColumn("Column1")
        Me.RadGridView1.Columns.Add(col)
    End Sub

    Private Sub RadButton1_Click(sender As Object, e As EventArgs) Handles RadButton1.Click
        Dim sw As New Stopwatch
        sw.Start()

        Me.RadGridView1.Rows.Clear()
        Me.RadGridView1.BeginUpdate()
        Dim RowInfo
        For ii = 1 To 100000
            RowInfo = Me.RadGridView1.Rows.AddNew
            RowInfo.Cells("Column1").Value = ii
        Next
        Me.RadGridView1.EndUpdate()

        sw.Stop()
        Console.WriteLine("Elapsed: " & sw.Elapsed.TotalSeconds)
    End Sub
End Class

Workaround: add data to a collection and use bound mode

To reproduce:
- Group the grid first. Make sure there are enough rows for two pages.
- Set the AutoSizeRows property to true.

Workaround:
Set AutoSizeRows to false while printing.

The display member for empty string value in GridViewComboBoxColumn is not displayed. The following code reproduces the issue:

GridViewComboBoxColumn cboInsRslCd = new GridViewComboBoxColumn();
cboInsRslCd.DataType = typeof(string);
List<ItemComboBox> liste = new List<ItemComboBox>();
liste.Add(new ItemComboBox("", "[None]"));
liste.Add(new ItemComboBox("A", "A"));
liste.Add(new ItemComboBox("B", "B"));
liste.Add(new ItemComboBox("C", "C"));

cboInsRslCd.DataSource = liste;
cboInsRslCd.ValueMember = "CleItem";
cboInsRslCd.DisplayMember = "ValeurItem";
cboInsRslCd.NullValue = "[None]";
this.radGridView1.Columns.Add(cboInsRslCd);

WORKAROUND:  subscribe to the CellEndEdit event and change the stored value in the event handler:
private void RadGridView1_CellEndEdit(object sender, GridViewCellEventArgs e)
{
    if (e.Value == null)
    {
        e.Row.Cells[e.Column.Name].Value = "";
    }
}

http://www.telerik.com/community/forums/radgridview-comboboxcolumn-displays-no-value-for-member-with-empty-string-value-is-selected

To reproduce:

1. Add a RadGridView and a RadButton.
2. Use the following code snippet:

Public Class Form1
    Private myList As New List(Of MyObject)
    Sub New()
        InitializeComponent()
        PopulateGrid(300)
    End Sub

    Private Sub RadButton1_Click(sender As Object, e As EventArgs) Handles RadButton1.Click
        PopulateGrid(100) 
    End Sub

    Private Sub PopulateGrid(count As Integer)
        myList.Clear()
        Me.RadGridView1.DataSource = Nothing
        For index = 1 To count
            myList.Add(New MyObject(index, "Item" & index)) 
        Next
        Me.RadGridView1.DataSource = myList
    End Sub

    Public Class MyObject
        Public Sub New(ByVal myInt As Integer, ByVal myString As String)
            _myInt = myInt
            _myString = myString
        End Sub
        Private _myInt As Integer
        Public Property MyInt() As Integer
            Get
                Return _myInt
            End Get
            Set(ByVal value As Integer)
                _myInt = value
            End Set
        End Property
        Private _myString As String
        Public Property MyString() As String
            Get
                Return _myString
            End Get
            Set(ByVal value As String)
                _myString = value
            End Set
        End Property
    End Class
End Class

3. Select the last item
4. Click the button

Workaround: use BindingList instead of List

To reproduce:
-add a RadGridView and use the following code:

public Form1()
{
    InitializeComponent();


    GridViewComboBoxColumn comboColumn = new GridViewComboBoxColumn("ComboBox column");
    comboColumn.DataSource = new List<string>() { "first", "second", "third" };
    radGridView1.Columns.Add(comboColumn);


    radGridView1.CellEditorInitialized += radGridView1_CellEditorInitialized;
}


private void radGridView1_CellEditorInitialized(object sender, GridViewCellEventArgs e)
{
    RadDropDownListEditor dropDownEditor = radGridView1.ActiveEditor as RadDropDownListEditor;
    RadDropDownListEditorElement dropDownEditorElement = dropDownEditor.EditorElement as RadDropDownListEditorElement;


    dropDownEditorElement.SelectedIndex = 0;
}


If you try to add a new row in the grid, the first item in the RadDropDownListEditor is selected. If you do not make any selection changes and press Enter key, the new row will not be added.


Workaround: use the DefaultValuesNeeded event for initializing RadDropDownListEditorElement's selectin

To reproduce:
- Add logo in the header and export the document.

Workaround:
void exporter_HeaderExported(object sender, ExportEventArgs e)
{
    PdfEditor ed = e.Editor as PdfEditor;
    using (MemoryStream ms = new MemoryStream())
    {
        System.Drawing.Image.FromFile(@"C:\img\delete.png").Save(ms, System.Drawing.Imaging.ImageFormat.Png);
        ed.TranslatePosition(e.Rectangle.Width - 30, e.Rectangle.Y);
        ed.DrawImage(ms, new System.Windows.Size(30,30));
    }
}

A child row does not appear in the view by using following code snippet:

GridViewRowInfo^ pNewRow = pTemplate->Rows->AddNew();
pNewRow->Cells["ChildNameColumn"]->Value = this->ChildTextBox->Text;
int count = radGridView1->ChildRows->Count;
pNewRow->Cells["ChildAddressColumn"]->Value = count.ToString()

Workaround: add new rows in the following manner:

private: System::Void button2_Click(System::Object^  sender, System::EventArgs^  e)
{
    // add child row
    GridViewTemplate^ pTemplate = radGridView1->MasterTemplate->Templates[0];
    GridViewRowInfo^ pNewRow = pTemplate->Rows->NewRow();
    pNewRow->Cells["ChildNameColumn"]->Value = this->ChildTextBox->Text;
    int count = radGridView1->ChildRows->Count;
    pNewRow->Cells["ChildAddressColumn"]->Value = count.ToString();
    pTemplate->Rows->Add(pNewRow);
}

To reproduce:  Dim dockmem As New MemoryStream
    Dim gridmem As New MemoryStream

    Public Sub SetData()

        ' dgvSelectList.DataSource = Nothing
        Dim dt As DataTable
        dt = New DataTable

        dt.Columns.Add("VENDCODE")
        dt.Columns.Add("VENDNAME")
        dt.Rows.Add("AA2", "Arthur")
        dt.Rows.Add("AA2", "Arthur")

        dgvSelectList.DataSource = dt
        dgvSelectList.BestFitColumns()
    End Sub

    Private Sub frmSelectListNG2_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        SetData()
        dgvSelectList.EnableFiltering = False
        'Save Grid and Dock layout settings to mem stream and simulate my process
        SaveSettings()
    End Sub

    Public Sub btnGO_Click(sender As System.Object, e As System.EventArgs) Handles btnGO.Click
        LoadSettings()
        dgvSelectList.SplitMode = RadGridViewSplitMode.Horizontal
        SetData()
        LoadSettings()
    End Sub

    Private Sub LoadSettings()
        gridmem.Position = 0
        dockmem.Position = 0
        dgvSelectList.LoadLayout(gridmem)
        rdkSelect.LoadFromXml(dockmem)
    End Sub

    Private Sub SaveSettings()
        gridmem.Position = 0
        dockmem.Position = 0
        dgvSelectList.SaveLayout(gridmem)
        rdkSelect.SaveToXml(dockmem)
    End Sub

Workaround - set the datasource to Nothing prior rebinding

Advanced Property Grid in Property Builder filter the data source list and not show 'Project Data Sources' for selection in the DataSource popup.

There is a difference in the drop down Datasource selection between the :
    GridviewDataColumn Collection Editor      and the...
    RadGridView Property Builder

To reproduce:
1.Add a GridViewCheckBoxColumn and populate the grid with data:
radGridView1.DataSource = Enumerable.Range(1, 100).Select(i => new { Check = i % 2 == 0});
2.Add a RadButton and on its Click event clear the filters:
private void radButton1_Click(object sender, EventArgs e)
{
    radGridView1.MasterTemplate.FilterDescriptors.Clear();
}
3.Run the application and change the filter to show only checked items. Then click the button. The check box in the filtering row for GridViewCheckBoxColumn was not updated properly.

Workaround:
this.radGridView1.BeginUpdate();
radGridView1.MasterTemplate.FilterDescriptors.Clear();
this.radGridView1.EndUpdate();

Workaround:

public Form1()
{
    InitializeComponent();
    radGridView1.CreateCell += radGridView1_CreateCell;
}
 
private void radGridView1_CreateCell(object sender, GridViewCreateCellEventArgs e)
{
    if (e.CellType == typeof(GridDataCellElement))
    {
        e.CellElement = new CustomDataCell(e.Column,e.Row);
    }
}
 
public class CustomDataCell : GridDataCellElement
{
    public CustomDataCell(GridViewColumn column, GridRowElement row) : base(column, row)
    {
    }
 
    protected override Type ThemeEffectiveType
    {
        get
        {
            return typeof(GridDataCellElement);
        }
    }
 
    protected override void OnMouseDown(MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left &&
            this.AllowRowReorder &&
            this.ViewTemplate.AllowRowReorder &&
            Cursor.Current != Cursors.SizeNS)
        {
            base.OnMouseDown(e);
        }
    }
}

The example found here http://www.telerik.com/support/kb/winforms/gridview/details/high-performance-with-radgridview-and-virtual-mode-including-filtering-sorting-and-grouping, currently does not work. There should be a way for the example virtual grid to go past the current limitation in sorting, filtering and grouping.

How to reproduce: just create a grid with a great number of rows e.g. 15000 and scroll down using the page down key

Workaround:
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        BaseGridBehavior gridBehavior = radGridView1.GridBehavior as BaseGridBehavior;
        gridBehavior.UnregisterBehavior(typeof(GridViewDataRowInfo));
        gridBehavior.RegisterBehavior(typeof(GridViewDataRowInfo), new CustomGridDataRowBehavior());

        DataTable dataTable = new DataTable();
        dataTable.Columns.Add("Id", typeof(int));
        dataTable.Columns.Add("Name", typeof(string));
        dataTable.Columns.Add("IsValid", typeof(bool));

        for (int i = 0; i < 14000; i++)
        {
            dataTable.Rows.Add(i, "Name " + i, i % 2 == 0 ? true : false);
        }

        this.radGridView1.DataSource = dataTable;
        this.radGridView1.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;
    }
}

public class CustomGridDataRowBehavior : GridDataRowBehavior
{
    protected override bool ProcessPageUpKey(KeyEventArgs keys)
    {
        GridTableElement tableElement = (GridTableElement)this.GridViewElement.CurrentView;
        int index = this.GridViewElement.CurrentRow.Index - tableElement.RowsPerPage + 1;
        if (index < 0)
        {
            index = 0;
        }

        GridViewRowInfo firstScrollableRow = this.GridControl.Rows[index];
        this.GridViewElement.CurrentRow = firstScrollableRow;

        return true;
    }

    protected override bool ProcessPageDownKey(KeyEventArgs keys)
    {
        GridTableElement tableElement = (GridTableElement)this.GridViewElement.CurrentView;
        int index = this.GridViewElement.CurrentRow.Index + tableElement.RowsPerPage - 1;
        if (index > this.GridControl.Rows.Count - 1)
        {
            index = this.GridControl.Rows.Count - 1;
        }

        GridViewRowInfo lastScrollableRow = this.GridControl.Rows[index];
        this.GridViewElement.CurrentRow = lastScrollableRow;

        return true;
    }
}

To reproduce: create a form with a button on it where on its Click event you show another form with the following code snippet:

public class Dummy
    {
        public int ID { get; set; }
        public string Description { get; set; }
    }

public Form1()
{
    InitializeComponent();
    this.radGridView1.FilterChanged += radGridView1_FilterChanged;

    if (File.Exists(@"..\..\..\layout.xml"))
    {
        this.radGridView1.LoadLayout(@"..\..\..\layout.xml");
    }
    else
    {
        radGridView1.Columns.Add(new GridViewTextBoxColumn { HeaderText = "Id ", FieldName = "ID" });
        radGridView1.Columns.Add(new GridViewTextBoxColumn { HeaderText = "Description", FieldName = "DESCRIPTION" });
    }
    radGridView1.EnableFiltering = true;
    radGridView1.MasterTemplate.ShowHeaderCellButtons = true;
    radGridView1.MasterTemplate.ShowFilteringRow = true;

    var items = new List<Dummy>();
    
    for (int i = 0; i < 20; i++)
    {
        var dummy = new Dummy
        {
            ID = i,
            Description = string.Format("Description_{0}", i)
        };
        
        items.Add(dummy);
    }
    radGridView1.AutoGenerateColumns = false;
    radGridView1.DataSource = items;
}

private void radGridView1_FilterChanged(object sender, GridViewCollectionChangedEventArgs e)
{
    this.radGridView1.SaveLayout(@"..\..\..\layout.xml");
}

Please refer to the attached gif file illustrating the steps.