The RadTokenizedTextItem should reference the data items as well. 

RadTextBox should indicate ReadOnly state

Add option to RadSpellChecker which will allow you to append the newly added words to the loaded dictionary and save them on the hard drive.

Add support for case sensitivity search in the suggested elements.

RadAutoCompleteBox - add functionality that allow you to show Popup without typing any char.

RadMaskedEditBox does not support G mask

Currently all spell checker dialogs are not accessible for customization.

first digit entered 3 would display 0.03
second digit 5 entered would display 0.35
third digit 0 entered  would display 3.50

Currently there can only be one delimiter in the autocomplete box. Different users might be accustomed to using different delimiters, even one user using several delimiters.

IMPROVE. RadTextBoxControl - add right to left support

Currently, this can be achieve with this code:
  TextInfo textInfo = new CultureInfo("en-US", false).TextInfo;
        bool updating = false;
        void radTextBox1_TextChanging(object sender, TextChangingEventArgs e)
        {
            if (!updating)
            {
                int pos = radTextBox1.TextBoxElement.TextBoxItem.SelectionStart;
                updating = true;
                radTextBox1.Text = textInfo.ToTitleCase(radTextBox1.Text);
                radTextBox1.TextBoxElement.TextBoxItem.SelectionStart = pos;
                updating = false;
            }
        }

Users should be able to increment the whole value of the RadMaskedEditBox using the Up/Down arrow keys or Mouse Wheel

ADD. RadTextBox - there should be a mode whether the undo should bring back the previous word or to work for each character

ADD. RadTextBox - add redo functionality

The textbox should increase its size when entering text.

One should be able to change the color of the RadTextBox text when it is disabled.

Workaround: override the ProcessCmdKey method of the form and activate the desired control:
 protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
        {
            if (keyData== Keys.Tab)
            {
                this.ActiveControl = this.radPopupEditor2.PopupEditorElement.TextBoxElement.TextBoxItem.HostedControl;
                return true;
            }
            return base.ProcessCmdKey(ref msg, keyData);
        }

IMPORTANT!!! Tab key should navigate to the next control even if the popup is opened.