To reproduce use the following configuration for the DateTimePicker:
public Form1()
{
    InitializeComponent();
    DateTime start = DateTime.Parse("2012/7/1 00:00:00");
    this.RadDateTimePicker1.ShowUpDown = true;
  
    this.RadDateTimePicker1.Format = DateTimePickerFormat.Custom;
    this.RadDateTimePicker1.DateTimePickerElement.ShowCurrentTime = false;
    this.RadDateTimePicker1.MinDate = start;
    this.RadDateTimePicker1.DateTimePickerElement.CustomFormat = "HH:mm";
    this.RadDateTimePicker1.MaxDate = start + TimeSpan.FromMinutes(1440);
    this.RadDateTimePicker1.Value = start +TimeSpan.FromMinutes(1);
    this.RadDateTimePicker1.Enter += new EventHandler(this.ConfigStartDelayTime_Enter);        
}

void ConfigStartDelayTime_Enter(object sender, EventArgs e)
{
    RadMaskedEditBoxElement element = this.RadDateTimePicker1.DateTimePickerElement.TextBoxElement.TextBoxItem.Parent as RadMaskedEditBoxElement;
    MaskDateTimeProvider provider = element.Provider as MaskDateTimeProvider;
    provider.SelectLastItem();
}

To reproduce:
- Add default .net RichTextBox to a blank form.
- Add a contexmenu strip (again .net one) to the RichTextBox.
- Spell check using RadSpellChecker and you will notice that the menu cannot be opened after that.

Workaround:
void richTextBox1_MouseDown(object sender, MouseEventArgs e)
{
    if (e.Button == System.Windows.Forms.MouseButtons.Right)
    {
        richTextBox1.ContextMenuStrip.Show(this.richTextBox1, e.Location);
    }
}

To reproduce:
- Open the RadColorDialogForm  (for example to edit color property in RadProeprtyGrid) 
- Switch to the web tab.
-Press the 'a' key several times.
 

When the control is disabled it size is changed/

Please refer to the attached picture.

Workaround:
private void Form1_Load(object sender, EventArgs e)
{
    this.radDateTimePicker1.DateTimePickerElement.CheckBox.CheckMarkPrimitive.CheckElement.Margin = new Padding(-2, -2, 0, 0);
}

Add a RadAutoCompleteBox with some data source and dock it to top of the Form.

Start the Application and stretch the form to the second screen. Autocomplete some items, you will notice that the dropdown will not be shown on the correct position. Also at some point when you are reaching the end of the first screen it will be displayed on the seconds screen.

Workaround:

(this.AutoCompleteBox.TextBoxElement as RadAutoCompleteBoxElement).AutoCompleteDropDown.PopupOpening += AutoCompleteDropDown_PopupOpening;

....

void AutoCompleteDropDown_PopupOpening(object sender, CancelEventArgs args)
{
    var e = args as RadPopupOpeningEventArgs;
    var popup = sender as RadTextBoxAutoCompleteDropDown;
    bool isOnTwoScreens = false;
    if (this.Location.X < Screen.PrimaryScreen.WorkingArea.Width && this.Location.X + this.Width > Screen.PrimaryScreen.WorkingArea.Width)
    {
        isOnTwoScreens = true;
    }

    if (popup.Width + e.CustomLocation.X > Screen.PrimaryScreen.WorkingArea.Width && isOnTwoScreens)
    {
        e.CustomLocation = new Point(e.CustomLocation.X - Screen.PrimaryScreen.WorkingArea.Width, e.CustomLocation.Y);
    }
}

If negative numbers are required to be displayed in brackets , e.g. ($1234,56) instead of -$1234,56, you should apply the desired NumberFormatInfo.CurrencyNegativePattern http://msdn.microsoft.com/en-us/library/system.globalization.numberformatinfo.currencynegativepattern(v=vs.110).aspx
However, the NumericCharacterTextBoxProvider clears the brackets.

CultureInfo culture = CultureInfo.CreateSpecificCulture("en-US");
NumberFormatInfo info = new NumberFormatInfo();
info.CurrencyNegativePattern = 0; 
info.CurrencySymbol = "$";
culture.NumberFormat = info;        
this.radMaskedEditBox2.Culture = culture;
this.radMaskedEditBox2.MaskType = Telerik.WinControls.UI.MaskType.Numeric;
this.radMaskedEditBox2.Mask = "c2";            
this.radMaskedEditBox2.Value = -1234.56; 

To reproduce: 

public Form1()
{
    InitializeComponent();

    this.radAutoCompleteBox1.AutoCompleteDataSource = ReturnDummyDataTable();
    this.radAutoCompleteBox1.AutoCompleteDisplayMember = "Sum";
    this.radAutoCompleteBox1.AutoCompleteValueMember = "Answer"; 
}

private DataTable ReturnDummyDataTable()
{
    DataTable dt = new DataTable();
    dt.Columns.Add("Sum");
    dt.Columns.Add("Answer");

    for (int i = 0; i <= 50; i++)
    {
        DataRow DR = default(DataRow);
        DR = dt.NewRow();
        DR[0] = i + " + 1";
        DR[1] = (i + 1);
        i += 1;
        dt.Rows.Add(DR);
    }

    return dt;
}

private void radButton1_Click(object sender, EventArgs e)
{
    string Buffer = "";
    if (this.radAutoCompleteBox1.Items.Count == 0)
    {
    }
    else
    {
        foreach (RadTokenizedTextItem item in this.radAutoCompleteBox1.Items)
        {
            if (Buffer.Length > 1)
            {
                Buffer = Buffer + Environment.NewLine + item.Text + " " + "= " + item.Value;
            }
            else
            {
                Buffer = item.Text + " " + "= " + item.Value;
            }
        }
        MessageBox.Show(Buffer, "Selected Items", MessageBoxButtons.OK, MessageBoxIcon.Information);
    }
}


Workaround: set the AutoCompleteDataSource property after setting the AutoCompleteDisplayMember and the AutoCompleteValueMember properties.

When one is typing using Chinese characters, each character is inserted twice.

To reproduce:
- Use the following mask:  "+56000000000".
- Then type 5 when the whole text is selected.
- The caret move to 5 instead of inserting it in the text box like in the default .NET control.

Resolution: 
TextBlockElement was removed from EditUI elements, since it is a dynamically added. 

To reproduce: add a RadTreeView and a timer. Use the following code:

BindingList<Item> list = new BindingList<Item>();

public Form1()
{
    InitializeComponent();
    this.radTreeView1.TreeViewElement.CreateNodeElement += TreeViewElement_CreateNodeElement;
   
    for (int i = 0; i < 10; i++)
    {
        list.Add(new Item(Guid.NewGuid().ToString(), "Node" + i));
    }

    this.radTreeView1.DataSource = list;
    this.radTreeView1.DisplayMember = "Title";
    this.radTreeView1.ValueMember = "UniqueIdentifier";

    this.radTreeView1.TreeViewElement.AutoSizeItems = true;
    this.timer1.Start();
}

void TreeViewElement_CreateNodeElement(object sender, Telerik.WinControls.UI.CreateTreeNodeElementEventArgs e)
{
    e.NodeElement = new CustomTreeNodeElement();
}

public class Item: System.ComponentModel.INotifyPropertyChanged
{
    public Item(string uniqueIdentifier, string title)
            {
                this._uniqueIdentifier = uniqueIdentifier;
                this._title = title;
            }

    public string UniqueIdentifier
            {
                get
                {
                    return this._uniqueIdentifier;
                }
                set
                {
                    this._uniqueIdentifier = value;
                    OnPropertyChanged("UniqueIdentifier");
                }
            }

    public string Title
            {
                get
                {
                    return this._title;
                }
                set
                {
                    this._title = value;
                    OnPropertyChanged("Title");
                }
            }

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName)
            {
                if (PropertyChanged != null)
                {
                    PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
                }
            }

    private string _uniqueIdentifier;
    private string _title;
}

public class CustomContentElement : TreeNodeContentElement
{
    StackLayoutElement nodeContentContainer;
    LinePrimitive lineElement;
    LightVisualElement idElement;
    RadTextBoxControlElement textBoxElement;

    protected override Type ThemeEffectiveType
            {
                get
                {
                    return typeof(TreeNodeContentElement);
                }
            }

    protected override void InitializeFields()
            {
                base.InitializeFields();
                this.Margin = new Padding(5, 5, 5, 5);

                this.StretchHorizontally = true;
            }

    public override void Synchronize()
    {
        this.DrawFill = true;

        TreeNodeElement treeNodeElement = this.NodeElement;
        RadTreeNode node = treeNodeElement.Data;
        Item dataItem = (Item)node.DataBoundItem;
        if (dataItem != null)
        {
            this.idElement.Text = string.Empty + dataItem.UniqueIdentifier;

            this.textBoxElement.Text = string.Empty + dataItem.Title;
        }
    }

    protected override void CreateChildElements()
            {
                nodeContentContainer = new StackLayoutElement();
                nodeContentContainer.Orientation = Orientation.Vertical;
                nodeContentContainer.StretchHorizontally = true;
                nodeContentContainer.StretchVertically = false;

                idElement = new LightVisualElement();
                idElement.ShouldHandleMouseInput = false;
                idElement.NotifyParentOnMouseInput = true;
                idElement.StretchVertically = false;
                this.nodeContentContainer.Children.Add(idElement);

                lineElement = new LinePrimitive();
                lineElement.BackColor = Color.Black;
                lineElement.Margin = new Padding(10, 0, 10, 0);
                lineElement.StretchVertically = false;
                this.nodeContentContainer.Children.Add(lineElement);

                textBoxElement = new RadTextBoxControlElement();
                textBoxElement.TextChanged += textBoxElement_TextChanged;
                textBoxElement.Margin = new Padding(20, 3, 20, 3);
                textBoxElement.StretchVertically = false;
                this.nodeContentContainer.Children.Add(textBoxElement);

                this.Children.Add(nodeContentContainer);
            }

    private void textBoxElement_TextChanged(object sender, EventArgs e)
    {
        RadTextBoxControlElement tb = sender as RadTextBoxControlElement;
        CustomContentElement contentElement = tb.Parent.Parent as CustomContentElement;
        Item item = contentElement.NodeElement.Data.DataBoundItem as Item;
        if (item.Title != tb.Text)
        {
            item.Title = tb.Text;
        }
    }
}

public class CustomTreeNodeElement : TreeNodeElement
{
    protected override TreeNodeContentElement CreateContentElement()
    {
        return new CustomContentElement();
    }

    protected override Type ThemeEffectiveType
    {
        get
        {
            return typeof(TreeNodeElement);
        }
    }
}

private void timer1_Tick(object sender, EventArgs e)
{
    foreach (Item item in list)
    {
        item.Title = "Node " + DateTime.Now.ToLongTimeString();
    }
}

To reproduce: use the following code:

this.radSpinEditor1.ScreenTipNeeded += screenTipNeeded;

 private void screenTipNeeded(object sender, Telerik.WinControls.ScreenTipNeededEventArgs e)
 {
     Console.WriteLine(e.Item);
     RadOffice2007ScreenTipElement screenTip = e.Item.ScreenTip as RadOffice2007ScreenTipElement;
     if (screenTip == null)
     {
         e.Item.ScreenTip = new RadOffice2007ScreenTipElement();
         screenTip = e.Item.ScreenTip as RadOffice2007ScreenTipElement;
     }
     screenTip.CaptionLabel.Text = "Title of tooltip";
     screenTip.MainTextLabel.Text = "Text of tooltip";
 }


Workaround:

this.radSpinEditor1.SpinElement.TextBoxItem.HostedControl.MouseLeave += radSpinEditor1_MouseLeave;

 private void radSpinEditor1_MouseLeave(object sender, EventArgs e)
 {
     if (this.radSpinEditor1.SpinElement.TextBoxItem.ScreenTip != null)
     {
         this.radSpinEditor1.ElementTree.ComponentTreeHandler.Behavior.HideScreenTip();
     }
 }

When you have a GridViewDateTimeColumn in the RadGridView and enter in edit mode, you are allowed to clear the current date (set it to null) pressing the Clear button in the popup calendar. However, this functionality is not available in the RadDateTimePicker control.

Workaround:

 public Form1()
 {
     InitializeComponent();
     this.radDateTimePicker1.NullText = "Empty";

     RadDateTimePickerCalendar calendarBehavior = this.radDateTimePicker1.DateTimePickerElement.GetCurrentBehavior() as RadDateTimePickerCalendar;
     calendarBehavior.Calendar.ShowFooter = true;
     calendarBehavior.Calendar.ClearButton.Click += ClearButton_Click;
 }

 private void ClearButton_Click(object sender, EventArgs e)
 {
     this.radDateTimePicker1.DateTimePickerElement.SetToNullValue();
 }