To reproduce:
- Set the AutoSelectNextPart property to true.
- Selelct the entire text and try to enter the date.

Workaround:
radTimePicker1.TimePickerElement.KeyDown += TimePickerElement_KeyDown;

void TimePickerElement_KeyDown(object sender, KeyEventArgs e)
{
    if (this.radTimePicker1.TimePickerElement.MaskedEditBox.TextBoxItem.Text.Trim('A', 'P', 'M', ' ') == this.radTimePicker1.TimePickerElement.MaskedEditBox.TextBoxItem.SelectedText.Trim('A', 'P', 'M', ' '))
    {
        ((MaskDateTimeProvider)radTimePicker1.TimePickerElement.MaskedEditBox.Provider).SelectFirstEditableItem();
        e.Handled = true;
    }
}

To reproduce:
 private void MdiChildForm_Load(object sender, EventArgs e)
 {
      radMaskedEditBox1.MaskType = MaskType.Numeric;
      radMaskedEditBox1.Mask = "n4";
      radMaskedEditBox1.NullText = "this is null text"
}
 private void radButton1_Click(object sender, EventArgs e)
{
      radMaskedEditBox1.Value = null;
 }

the issue appears also when the RadmaskedEditBox is configured like this:

this.radMaskedEditBox1.MaskType = Telerik.WinControls.UI.MaskType.Standard;
this.radMaskedEditBox1.Mask = "0000000";

this.radMaskedEditBox1.NullText = "My null text";
this.radMaskedEditBox1.PromptChar = '_';

WORKAROUND:
radMaskedEditBox1.Value = null;
radMaskedEditBox1.MaskedEditBoxElement.TextBoxItem.HostedControl.Text = "";

When you inherit from RadTextBox and override the OnKeyPress or OnKeyDown, those events are not fired.

To reproduce: 
1. Add UserControl
2. Drag and drop RadPopupEditor and RadPopupContainer
3. Open the smart tag of RadPopupEditor and try to set the AssociatedControl property. You will see error message from attached image. 

Workaround: 
Set the AssociatedControl at run time. Here is the code snippet: 

For C#: 
public UserControl1()
{
    InitializeComponent();
    this.radPopupEditor1.AssociatedControl = this.radPopupContainer1;
}

For VB:
Public Class UserControl1
    Inherits UserControl
    Public Sub New()
        InitializeComponent()
        Me.RadPopupEditor1.AssociatedControl = Me.RadPopupContainer1
    End Sub
End Class

Workaround:
        RadPopupContainer1.BindingContext = New BindingContext()

Keyboard input does not work in RadDateTimePicker when the Culture is ar-SA

ADD. Popup control which can host controls and be associated with a button or opened on request.

To reproduce:
1. Add a RadTextBox
2. Set the AutoCompleteMode property to SuggestAppend 
3. Add a RadSpellChecker and set the AutoSpellCheckControl property  the text box
4. Start typing. You will notice that the autocomplete functionality behaves as expected. But the incorrect words are not underlined. 

Workaround:  use RadTextBoxControl

To reproduce: use the following code:

public Form1()
{
    InitializeComponent();

    Label l1 = new Label();
    l1.Text = "Label&1";
    l1.Location = new Point(10, 20);
    this.Controls.Add(l1);

    RadTextBox tb = new RadTextBox();
    tb.Location = new Point(150, 20);
    this.Controls.Add(tb);

    Label l2 = new Label();
    l2.Text = "Label&2";
    l2.Location = new Point(10, 50);
    this.Controls.Add(l2);

    RadTextBoxControl tbc = new RadTextBoxControl();
    tbc.Location = new Point(150, 50);
    this.Controls.Add(tbc);

    Label l3 = new Label();
    l3.Text = "Label&3";
    l3.Location = new Point(10, 80);
    this.Controls.Add(l3);

    RadMaskedEditBox meb = new RadMaskedEditBox();
    meb.Location = new Point(150,80);
    this.Controls.Add(meb);
}

If you press Alt +2, the RadTextBoxControl will get focus. However, if you press Alt + 3, the RadMaskedEditBox will not display the caret. The control actually gets focus, but the inner text box does not.

Workaround: 
private void radMaskedEditBox1_GotFocus(object sender, EventArgs e)
{
    this.radMaskedEditBox1.MaskedEditBoxElement.TextBoxItem.TextBoxControl.Focus();
}

Workaround: 

this.radTextBoxControl1.TextBoxElement.AutoCompleteDropDown.PopupOpening += AutoCompleteDropDown_PopupOpening;

private void AutoCompleteDropDown_PopupOpening(object sender, CancelEventArgs args)
{
    RadPopupOpeningEventArgs a = args as RadPopupOpeningEventArgs;
    if (a != null )
    {
        a.CustomLocation = new Point(a.CustomLocation.X,a.CustomLocation.Y + 20);
    }
}

Place a RadTextBox on a form and set its anchor to Left, Top, Right. Show the form in a maximized mode. You will notice that the RadTextBox is longer than it should be. The workaround concerns setting the AutoSize property of RadTextBox to false.

Workaround:

            this.radDateTimePicker1.DateTimePickerElement.ShowTimePicker = true; 
            RadDateTimePickerCalendar calendarBehavior = this.radDateTimePicker1.DateTimePickerElement.GetCurrentBehavior() as RadDateTimePickerCalendar;
            calendarBehavior.PopupControl.Opened += PopupControl_Opened;
            calendarBehavior.PopupControl.Opening+=PopupControl_Opening;
            calendarBehavior.PopupControl.Closing+=PopupControl_Closing;
            calendarBehavior.PopupControl.Closed+=PopupControl_Closed;

Please refer to the attached gif file.

Workaround:

public Form1()
{
    InitializeComponent();

    this.radSpellChecker1.AutoSpellCheckControl = this.radTextBoxControl1;
    this.radTextBoxControl1.Multiline = true;
    this.radTextBoxControl1.ContextMenuOpening += radTextBoxControl1_ContextMenuOpening;
}

public static bool containsError = false;
public static bool isMisspelledWord = true;

private void radTextBoxControl1_ContextMenuOpening(object sender, TreeBoxContextMenuOpeningEventArgs e)
{
    if (!isMisspelledWord && containsError)
    {
        //do not show the context when you click over a correct word
        e.Cancel = true;
    }
}

public class MyTextBox : RadTextBoxControl
{
    protected override RadTextBoxControlElement CreateTextBoxElement()
    {
        return new MyTextBoxElement();
    }

    public override string ThemeClassName
    {
        get
        {
            return typeof(RadTextBoxControl).FullName;
        }
    }
}

public class MyTextBoxElement : RadTextBoxControlElement
{
    RadSpellChecker sp = new RadSpellChecker();

    protected override void OnMouseDown(MouseEventArgs e)
    {
        sp.AutoSpellCheckControl = this.ElementTree.Control;
        containsError = false;
        isMisspelledWord = true;
        if (e.Button == System.Windows.Forms.MouseButtons.Right)
        {
            Point location = this.ElementTree.Control.PointToClient(Cursor.Position);
            TextPosition position = this.Navigator.GetPositionFromPoint(location);
            this.Navigator.CaretPosition = position;

            if (this.Multiline)
            {
                this.Navigator.ScrollToCaret();
            }
            ITextBoxNavigator navigator = this.Navigator;

            TextPosition caretPosition = navigator.CaretPosition;
            LineInfo line = caretPosition.Line;
            ITextBlock textBlock = caretPosition.TextBlock;
            string clickedWordInRadTextBox = textBlock.Text;
            if (string.IsNullOrEmpty(clickedWordInRadTextBox) || clickedWordInRadTextBox == " ")
            {
                return;
            }
            TextBoxSpellChecker tbSpellChecker = sp.GetControlSpellChecker(typeof(RadTextBoxControl)) as TextBoxSpellChecker;
            ICollection<string> suggestions = tbSpellChecker.SpellChecker.GetSuggestions(clickedWordInRadTextBox);

            if (suggestions.Count > 0)
            {
                containsError = true;
            }

            if (tbSpellChecker.SpellChecker.CheckWordIsCorrect(clickedWordInRadTextBox))
            {
                isMisspelledWord = false;
            }
            base.OnMouseDown(e);
        }
    }

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

To reproduce:
- Set the value of the TimePicker to a value that is different from the current day.
- Select the time part and press the up arrow button.

To reproduce:
AddHandler RadAutoCompleteBox1.Validating, Sub()
                                               'add new item to list
                                               Dim txt As String = RadAutoCompleteBox1.Text
                                               Dim add As String = String.Empty
                                               If Not String.IsNullOrEmpty(txt) Then
                                                   If Not txt.EndsWith(";") Then
                                                       'new item!
                                                       If txt.Contains(";") Then
                                                           _addWg = txt.Split(";").Last
                                                       Else
                                                           _addWg = txt
                                                       End If
                                                       RadAutoCompleteBox1.Text = RadAutoCompleteBox1.Text & ";"
                                                   End If
                                               End If
                                           End Sub

'---------------
'We update the datasource when we lost focus....
AddHandler RadAutoCompleteBox1.LostFocus, Sub()
                                              If Not String.IsNullOrEmpty(_addWg) AndAlso Not wgAcSource.Contains(_addWg) Then
                                                  wgAcSource.Add(_addWg)
                                                  RadAutoCompleteBox1.AutoCompleteDataSource = Nothing
                                                  RadAutoCompleteBox1.AutoCompleteDataSource = wgAcSource
                                                  _addWg = String.Empty
                                              End If

                                          End Sub


Workaround:
Add the item and reset the data source in the KeyDown event for example when the user presses Enter.

To reproduce:
-add a RadTimePicker;
-change its culture:
this.radTimePicker1.Culture = new System.Globalization.CultureInfo("en-GB");

Workaround:
public Form1()
{
    InitializeComponent();

    this.radTimePicker1.Culture = new System.Globalization.CultureInfo("en-GB");
    this.radTimePicker1.TimePickerElement.PopupForm.Height =350;
   
}

When you set a specific value to the RadTimePicker e.g.  new DateTime(2014, 5, 20, 8, 15, 30) and try to change the time via mouse wheel or up/down arrows, the date part is reset to DateTime.Now.

Resolution: 
This broke RadTimePicker functionality because many users have serialized in designer.cs/vb files MinValue and MaxValues and now they date part is take  under consideration - this can complete broke its application. Users should keep the date part in separate variable not in TimePicker Value property

FIX. RadDropDownList- when the form is started the textbox shows the end of the text instead of the begging of it, when the used text is longer than the control length.

To reproduce: Change the monitors positions in the settings panel and try out on both monitors. Please refer to the attached file.

Workaround:

Dim tbLocation = Point.Empty
Sub New()
    InitializeComponent()
    Me.RadTextBox1.Text = "Once uppon "
    Dim tbSpellChecker As TextBoxSpellChecker = Me.RadSpellChecker1.GetControlSpellChecker(GetType(RadTextBox))
    AddHandler tbSpellChecker.DropDownMenu.PopupOpening, AddressOf PopupOpening
    AddHandler Me.RadTextBox1.TextBoxElement.TextBoxItem.HostedControl.MouseDown, AddressOf RadTextBox1_MouseDown
End Sub

Private Sub PopupOpening(sender As Object, args As System.ComponentModel.CancelEventArgs)
    Dim e As RadPopupOpeningEventArgs = TryCast(args, RadPopupOpeningEventArgs)
    If e IsNot Nothing Then
        e.CustomLocation = tbLocation
    End If
End Sub

Private Sub RadTextBox1_MouseDown(sender As Object, e As MouseEventArgs)
    If e.Button = Windows.Forms.MouseButtons.Right Then
        tbLocation = Me.RadTextBox1.PointToScreen(e.Location)
    End If
End Sub