Use attached to reproduce:
- Disable and then enable the RadSateTimePicker
- You will notice that even the checkbox is unchecked the control is enabled. 

Workaround:

radDateTimePicker1.Enabled =true;
if (!radDateTimePicker1.DateTimePickerElement.Checked)
{
    radDateTimePicker1.DateTimePickerElement.TextBoxElement.TextBoxItem.HostedControl.Enabled = false;
}

To reproduce: please refer to the attached sample project and follow the steps from the provided gif file.

Workaround: use RadTextBoxControl.

Set the format:

dateTimePicker1.Format = DateTimePickerFormat.Custom;
dateTimePicker1.CustomFormat = "dd/MM/yyyy";

Enter 18 in the yaer part, the year should be set to 2018, the year should be cleared when starting to type as well.

Use the following code snippet:

            this.radMaskedEditBox1.Mask = "99/99/99/99/99/99";
            this.radMaskedEditBox1.MaskType = Telerik.WinControls.UI.MaskType.Standard;
            this.radMaskedEditBox1.PromptChar = ' ';
            ((StandartMaskTextBoxProvider)this.radMaskedEditBox1.MaskedEditBoxElement.Provider).TryGetStandardProvider().InsertKeyMode = InsertKeyMode.Overwrite;

When the cursor is just before the last "/", if you enter a number, then the cursor does not move after this last "/". Then entering another digit overwrites the last digit typed.

The workaround in the following MSDN resources results in an incorrect behavior in the header of RadDateTimePicker: https://code.msdn.microsoft.com/Fixing-Persian-Locale-for-6e66e044#content

To reproduce:
radPopupEditor1.PopupForm.VerticalPopupAlignment = VerticalPopupAlignment.TopToBottom;

Workaround:
private void RadPopupEditor1_PopupOpening(object sender, CancelEventArgs e)
{
    var args = e as RadPopupOpeningEventArgs;
    args.CustomLocation = new Point(args.CustomLocation.X, args.CustomLocation.Y - (radPopupEditor1.Height + radPopupEditor1.PopupForm.Height));
}

See attached video to reproduce.

Use attached to reproduce.

Workaround: 
Use RadTextBox.

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

Then enter 123.45

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

Using UI for WinForms R3 2017 (version 2017.3.912)

Strange behavior while selecting text with the mouse, while TextAlign is set to Right and there is more text then visible.
To reproduce try selecting all the text in the control from the attached file (once to the left, once to the right).

If the ShowClear button is visible and RihtToLeft is true, it won't select to the left (while there is more text than visible).


RadTextBoxControl radTextBoxControl1 = new Telerik.WinControls.UI.RadTextBoxControl();

this.radTextBoxControl1.Location = new System.Drawing.Point(239, 186);
this.radTextBoxControl1.Name = "radTextBoxControl1";
this.radTextBoxControl1.RightToLeft = System.Windows.Forms.RightToLeft.Yes;
this.radTextBoxControl1.ShowClearButton = true;
this.radTextBoxControl1.Size = new System.Drawing.Size(64, 20);
this.radTextBoxControl1.TabIndex = 6;
this.radTextBoxControl1.Text = "123456789123456789";
this.radTextBoxControl1.TextAlign = System.Windows.Forms.HorizontalAlignment.Right;

The suggestion must popup after every word.
There should be an option for positioning the drop down inside the textbox.

 

Windows TextBox - OSK perfect

Telerik RadTextBox - OSK perfect

Telerik RadTextBoxControl - OSK doesn't work

Telerik RadDropDownList - OSK doesn't work

Telerik AutoCompleteBox - OSK doesn't work

This should work for all controls that have text input.

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

Note: this issue is relevant for RadDropDownList as well.

Workaround:             
            this.radDropDownList2.DropDownListElement.TextBox.TextBoxItem.Multiline = true;
            this.radDropDownList2.DropDownListElement.TextBox.TextBoxItem.MinSize  = new Size(30, 15); 

How to reproduce: also check the attached video
this.radMaskedEditBox1.MaskType = MaskType.Numeric;

Workaround:
private void RadMaskedEditBox1_TextChanged(object sender, EventArgs e)
{
    if (this.radMaskedEditBox1.Text == "-0")
    {
        if (this.radMaskedEditBox1.MaskedEditBoxElement.TextBoxItem.Text.Length == 2)
        {
            //Workaround
            this.radMaskedEditBox1.MaskedEditBoxElement.TextBoxItem.Text = this.radMaskedEditBox1.MaskedEditBoxElement.TextBoxItem.Text.Remove(1, 1);
        }
    }
}

To reproduce:
 radTimePicker1.Value = DateTime.Now.AddDays(10);
 radTimePicker1.TimePickerElement.MaskedEditBox.MaskType = Telerik.WinControls.UI.MaskType.FreeFormDateTime;

Workaround:

protected override void OnLoad(EventArgs e)
{
    base.OnLoad(e);
    radTimePicker1.Value = DateTime.Now.AddDays(10);

    var provider = radTimePicker1.TimePickerElement.MaskedEditBox.Provider as FreeFormDateTimeProvider;

    provider.MinDate = DateTime.MinValue;
    provider.MaxDate = DateTime.MaxValue;
}

To reproduce use the following code and zoom to Years level:
this.radDateTimePicker1.Culture = new System.Globalization.CultureInfo("ps-AF");
radDateTimePicker1.DateTimePickerElement.Calendar.HeaderNavigationMode = Telerik.WinControls.UI.HeaderNavigationMode.Zoom;

To reproduce: use the following code snippet  and try to input some numeric value

public RadForm1()
 {
     InitializeComponent(); 
     this.radMaskedEditBox1.MaskType = Telerik.WinControls.UI.MaskType.Numeric; 
     this.radMaskedEditBox1.ValueChanged += radMaskedEditBox1_ValueChanged;
 }

 private void radMaskedEditBox1_ValueChanged(object sender, EventArgs e)
 {
     Console.WriteLine(this.radMaskedEditBox1.Value);
 }

Note: when you open the spell check dialog  and it iterates through the words, it does not highlight (select) the word in the linked RadTextBoxControl/RadTextBox, like it does in the Word's spell checker. 

One should be able to move to the next/previous word with Ctrl + right/left