To reproduce:
- Set the mask to numeric.
- Change the value and check the Modified property.

- Workaround:
string oldValue = string.Empty;

void radMaskedEditBox1_LostFocus(object sender, EventArgs e)
{
    if (oldValue != radMaskedEditBox1.Text)
    {
        radMaskedEditBox1.Modified = true;
    }
    else
    {
        radMaskedEditBox1.Modified = false;
    }

    oldValue = radMaskedEditBox1.Text;
}

To reproduce: handle the following event and start typing in the editable part. You will notice that the TextChanged event is not fired:
Me.RadPopupEditor1.DropDownStyle = Telerik.WinControls.RadDropDownStyle.DropDown
AddHandler Me.RadPopupEditor1.TextChanged, AddressOf RadPopupEditor1_TextChanged

Workaround: handle the RadPopupEditor.TextBoxElement.TextChanged event instead.

To reproduce:
public Form1()
{
    InitializeComponent();
    AddDateTime();
    radDateTimePicker1.ValueChanged += radDateTimePicker1_ValueChanged;
  
    radDateTimePicker1.Format = DateTimePickerFormat.Custom;
    radDateTimePicker1.CustomFormat = "dd/MM/yyyy HH:mm";

    AddButton();

}

void radDateTimePicker1_ValueChanged(object sender, EventArgs e)
{
    if (radDateTimePicker1.Value.Date.Hour == 0)
    {
        var date = radDateTimePicker1.Value.Date;
        radDateTimePicker1.Value = new DateTime(date.Year, date.Month, date.Day, 23, 59, 0);
    }
   
}

Workaround: 
Refocus the control and the value will be updated.

To reproduce:
- Disable the control.
- The text box has a white background.

- Workaround:
Set the  back color of the RadTimeMaskedEditBoxElement in for the disabled state in Visual Style Builder. 

To reproduce:
this.radTextBox1.Text = "sample";
this.radTextBox1.TextBoxElement.BackColor = Color.Red;
this.radTextBox1.TextBoxElement.UseDefaultDisabledPaint = false;
this.radTextBox1.TextBoxElement.Enabled = false;

In previous version (e.g. Q1 2014 SP1) the TextBoxElement is not rendered red.

When you drag a RadDateTimePicker from the Toolbox and drop it onto the form, the TabStop property is false by default. If you change it in the Properties grid to true and save the form, try to open the form designer again. As a result the TabStop property is set to false as if no changes have been performed.

Please refer to the attached screenshot.

Workaround: Me.RadDateTimePicker1.DateTimePickerElement.TextBoxElement.MaxSize = New Size(0, 20)

With the RadMaskedEditBox and MaskType set to Numeric and using simple data binding the mask is not being displayed properly

As a workaround handle ValueChanged event and apply the formatting in this event:
       dim alreadyExecuted as Boolean
       Sub ValueChange(sender As Object, e As EventArgs) Handles EditBoxWithBinding.ValueChanged 
	If Not alreadyExecuted Then 
		alreadyExecuted = True EditBoxWithBinding.MaskedEditBoxElement.Provider.Validate(EditBoxWithBinding.Value.ToString()) 
		alreadyExecuted = False 
	End If 
End Sub

To reproduce:

this.radDateTimePicker1.ThemeName = "TelerikMetroTouch";
var calendar1 = (radDateTimePicker1.DateTimePickerElement.CurrentBehavior as RadDateTimePickerCalendar);
calendar1.ShowTimePicker = true;

Workaround:

calendar1.Calendar.Width = 250;
calendar1.DropDownMinSize = new System.Drawing.Size(500, 250);

How to reproduce:
Check also the attached video

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

    private void radButton1_Click(object sender, EventArgs e)
    {
        this.radAutoCompleteBox1.AutoCompleteItems.Clear();

        List<RadListDataItem> autoCompleteEntries = new List<RadListDataItem>();
        for (int i = 0; i < 10000; i++)
        {
            autoCompleteEntries.Add(new RadListDataItem("Joe Smith", "joe@fakecompany.com"));
            autoCompleteEntries.Add(new RadListDataItem("Adam Petersen", "adam@qwerty.com"));
            autoCompleteEntries.Add(new RadListDataItem("Jack Russel", "jack@russel.nocom"));
            autoCompleteEntries.Add(new RadListDataItem("Daniel Finger", "daniel.pinger@gmail.com"));
            autoCompleteEntries.Add(new RadListDataItem("Richard Vail", "rvail@richardvail.com"));
            autoCompleteEntries.Add(new RadListDataItem("Sebastian Jonnson", "s.jonnson@sjonnson.com"));
            autoCompleteEntries.Add(new RadListDataItem("Lee Cooper", "lee.cooper@coopercoorp.com"));
            autoCompleteEntries.Add(new RadListDataItem("Kelvin Clain", "kclain@clainkevin.com"));
            autoCompleteEntries.Add(new RadListDataItem("Maria Jenson", "mjenson@mariajenson.com"));
            autoCompleteEntries.Add(new RadListDataItem("Chelsea Maarten", "chelsea@maarten.com"));
        }

        this.radAutoCompleteBox1.AutoCompleteItems.AddRange(autoCompleteEntries);
    }
}

Workaround: use Begin/End update block and reset the private patternText field:
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void radButton1_Click(object sender, EventArgs e)
    {
        typeof(RadTextBoxListElement).GetField("patternText", BindingFlags.Instance | BindingFlags.NonPublic).SetValue(this.radAutoCompleteBox1.ListElement, null);

        this.radAutoCompleteBox1.AutoCompleteItems.Clear();

        List<RadListDataItem> autoCompleteEntries = new List<RadListDataItem>();
        for (int i = 0; i < 10000; i++)
        {
            autoCompleteEntries.Add(new RadListDataItem("Joe Smith", "joe@fakecompany.com"));
            autoCompleteEntries.Add(new RadListDataItem("Adam Petersen", "adam@qwerty.com"));
            autoCompleteEntries.Add(new RadListDataItem("Jack Russel", "jack@russel.nocom"));
            autoCompleteEntries.Add(new RadListDataItem("Daniel Finger", "daniel.pinger@gmail.com"));
            autoCompleteEntries.Add(new RadListDataItem("Richard Vail", "rvail@richardvail.com"));
            autoCompleteEntries.Add(new RadListDataItem("Sebastian Jonnson", "s.jonnson@sjonnson.com"));
            autoCompleteEntries.Add(new RadListDataItem("Lee Cooper", "lee.cooper@coopercoorp.com"));
            autoCompleteEntries.Add(new RadListDataItem("Kelvin Clain", "kclain@clainkevin.com"));
            autoCompleteEntries.Add(new RadListDataItem("Maria Jenson", "mjenson@mariajenson.com"));
            autoCompleteEntries.Add(new RadListDataItem("Chelsea Maarten", "chelsea@maarten.com"));
        }

        this.radAutoCompleteBox1.ListElement.DataLayer.ListSource.BeginUpdate();
        this.radAutoCompleteBox1.AutoCompleteItems.AddRange(autoCompleteEntries);
        this.radAutoCompleteBox1.ListElement.DataLayer.ListSource.EndUpdate();
    }
}

Steps to reproduce:
Set MaskType to Numeric and Mask = "n2". Click into the field to deselect contents. Caret is at the end of the string. Backspace twice and the data entry caret now jumps to BEFORE the decimal point. 

Workaround:
this.RadMaskedEditBox.KeyPress += new KeyPressEventHandler(RadMaskedEditBox_KeyPress);
		}

        void RadMaskedEditBox_KeyPress(object sender, KeyPressEventArgs e)
        {
            RadMaskedEditBox textBox = ((RadMaskedEditBox)sender);
            int selectionStart = textBox.SelectionStart;
            bool beforePoint = selectionStart - 2 >= 0 && textBox.Text[selectionStart - 2] == '.';

            if (e.KeyChar == 8 && beforePoint)
            {                
                NumericMaskTextBoxProvider numericProvider = (NumericMaskTextBoxProvider)textBox.MaskedEditBoxElement.Provider;
                numericProvider.KeyPress(sender, e);
                e.Handled = true;
                textBox.SelectionStart++;
            }
        }

To reproduce:
radMaskedEditBox1.MaskType = MaskType.Numeric;
radMaskedEditBox1.Mask = "G";

Then enter 123.45

Workaround:
Use "N" mask with fixed decimal places.

To reproduce: add a RadMaskedEditBox and use the following code:

Sub New()

    InitializeComponent()

    Me.RadMaskedEditBox1.MaskType = Telerik.WinControls.UI.MaskType.Numeric
    Me.RadMaskedEditBox1.Mask = "N1"
        Dim item As Item = New Item(Nothing, "Item1")
    RadMaskedEditBox1.DataBindings.Add("Value", item, "StockTypeId", True, DataSourceUpdateMode.OnPropertyChanged)
End Sub

Public Class Item
    Private _stockId As Nullable(Of Integer)

    Public Sub New(value As Nullable(Of Integer), name As String)
        Me._stockId = value
    End Sub

    Public Property StockTypeId() As Nullable(Of Integer)
        Get
            Return _stockId
        End Get
        Set(ByVal value As Nullable(Of Integer))
            _stockId = value
            Console.WriteLine(value)
        End Set
    End Property
End Class

The user is not allowed to enter a new numeric value.

Wokraround:

Public Class CustomNumericCharacterTextBoxProvider
    Inherits NumericCharacterTextBoxProvider

    Private owner As RadMaskedEditBoxElement
    Public Sub New(mask As String, culture As CultureInfo, numericType As NumericCharacterTextBoxProvider.RadNumericMaskFormatType, _
    owner As RadMaskedEditBoxElement)
        MyBase.New(mask, culture, numericType, owner)
        Me.owner = owner
    End Sub
    Protected Overrides Function AllowAppendCharacters() As Boolean
        If owner.Text = "" AndAlso owner.Mask = "N1" Then
            Return True
        End If

        Return MyBase.AllowAppendCharacters()
    End Function
End Class

Public Class CustomMaskedEditBox
    Inherits RadMaskedEditBox

    Public Overrides Property ThemeClassName As String
        Get
            Return GetType(RadMaskedEditBox).FullName
        End Get
        Set(value As String)
            MyBase.ThemeClassName = value
        End Set
    End Property

    Public Sub New()
        MyBase.New()
        Me.MaskType = Telerik.WinControls.UI.MaskType.Numeric
        Me.Mask = "N1"
        Dim numericMaskProvider As NumericMaskTextBoxProvider = Me.MaskedEditBoxElement.Provider
        Dim fi As FieldInfo = GetType(NumericMaskTextBoxProvider).GetField("provider", BindingFlags.Instance Or BindingFlags.NonPublic)
        fi.SetValue(numericMaskProvider, _
                    New CustomNumericCharacterTextBoxProvider(numericMaskProvider.Mask, numericMaskProvider.Culture, _
                    NumericMaskTextBoxProvider.GetFormat(numericMaskProvider.Mask, numericMaskProvider.Culture), _
                    Me.MaskedEditBoxElement))

    End Sub
End Class

The RadTokenizedTextItem should reference the data items as well. 

To reproduce:
- Change the culture of the RadDateTime picker to Russian.
- Change the month to August and select the month part when the drop down is closed.

Workaround:
radDateTimePicker1.Format = DateTimePickerFormat.Custom;
radDateTimePicker1.CustomFormat = "dd/MMM/yyyy";

RadMaskedEditBox - At design time the NullText is not synchronized with the NullDate property.
I was able to Set NullText to "aaa", set the NullDate to 24/02/2012 and set the Value and 24/02/2012 and see after that the NullText

All controls (i.e. RadGridView, RadPropertyGrid, etc.), which use textbox editor, containing HostedTextBoxBase descendant, can be spelled by the RadSpellChecker. But the red underline is not displayed entirely. The inside hosted text box should have a bigger height.

RadDateTimePicker ValueChanging event cannot be canceled with e.Cancel = true;

Allow the RadDateTimePicker editor of RadGridView to allow replacement of the months' popup.

Resolution:   This behavior can be achieved when set the HeaderNavigationMode property to Zoom of RadCalendar. The feature is introduced in Q2 2014.  
For example: 
void radGridView1_CellEditorInitialized(object sender, Telerik.WinControls.UI.GridViewCellEventArgs e)
        {
            RadDateTimeEditor dtEditor = e.ActiveEditor as RadDateTimeEditor;
            if (dtEditor != null)
            {
                RadDateTimeEditorElement element = (RadDateTimeEditorElement)dtEditor.EditorElement;
                element.Calendar.HeaderNavigationMode = HeaderNavigationMode.Zoom;
            }
        }