To reproduce:
- Add two tabs in a PageView
- Add RadRichTextEditor in the second tab
- Select some text to show the mini toolbar 
- Select the first page.

Workaround
void radPageView1_SelectedPageChanged(object sender, EventArgs e)
{
    if (radPageViewPage2.IsContentVisible == false)
    {
        radRichTextEditor1.RichTextBoxElement.SelectionMiniToolBar.Hide();
    }
}

To reproduce:
- Add comment and try to select the text with the mouse.

Workaround: use keyboard to select the desired text

To reproduce:
- Create a document in Word and add image watermark to it.
- Open the document in RadRichtextEditor

To reproduce: 
1. Create a UserControl.
2. Drag from the Toolbox a RichTextEditorRibbonBar and drop it onto the UserControl.
3. Use the following code:
Sub New()
    InitializeComponent()
    Me.RichTextEditorRibbonBar1.CloseButton = False
    Me.RichTextEditorRibbonBar1.MinimizeButton = False
    Me.RichTextEditorRibbonBar1.MaximizeButton = False
End Sub

You will notice that the header is cut off.

Workaround: in order to hide the system buttons, use the following code:

 Me.RichTextEditorRibbonBar1.RibbonBarElement.RibbonCaption.SystemButtons.Visibility = Telerik.WinControls.ElementVisibility.Hidden

To reproduce:

Import the attached sample.html in RadRichTextEditor. Afterwards, export the content by using HtmlFormatProvider. You will notice that the page breaks are not exported and if you import the exported file, you will see the difference. Please refer to the attached screenshot.

To reproduce:
- Export rtf file with a bullet list - use the old RadRichTextBox.
- Import the file in the RadRichTextEditor in WebLayout mode.
- The entire list is shifted to the left and the bullets are not visible.

The issue is present because the old RadRichTextBox was exporting bullets with negative indent and the WebLayout mode always starts from 0.

To reproduce:
- Create new application with a richtextbox in it.
- Build it and merge the assemblies.
- Start the application type some text then select a part of it and try to do something else.
- Note that this occur only the first time when the application is started.

1) Launch the RadRichTextEditor
2) enter some text (at least three lines)
3) select the whole content and apply bullets/ numbers 
5) Since the whole content is already selected, open the font color dialog box and try to apply a color (say red color)
6) Notice for the last item in the list , the selected color is not applied to the bullets/ numbers as shown in the attached figs

To reproduce:
- Import an html text snippet several times (the text should exceed one page)
- Select the entire text and bold it.
- Now make the text Italic
- You will notice that the text is not bold anymore.
 

To reproduce:

Open TelerikEditor and underline the whole text. Go to the end of a line and hold space. You will notice that the empty spaces are being underlined. The behavior is not the same as in Word.

Workaround:

Remove the underlining of the empty spaces at the end of the lines:

void Button_Click(object sender, EventArgs e)
{
    var caret = this.richTextBox.Document.CaretPosition;
    var originalPosition = new DocumentPosition(caret);
    caret.MoveToFirstPositionInDocument();
    do
    {
        caret.MoveToCurrentLineEnd();
        var endPos = new DocumentPosition(caret);

        caret.MoveToCurrentWordStart();
        caret.MoveToCurrentWordEnd();

        var startPos = new DocumentPosition(caret);

        this.richTextBox.Document.Selection.AddSelectionStart(startPos);
        this.richTextBox.Document.Selection.AddSelectionEnd(endPos);
        this.richTextBox.ChangeUnderlineDecoration(UnderlineType.None);
        this.richTextBox.Document.Selection.Clear();

        caret.MoveToCurrentLineEnd();

    }
    while (caret.MoveToNext());

    caret.MoveToPosition(originalPosition);
}

Beware that this workaround will not work in all cases. It should be used only prior to exporting or similar cases

To reproduce:
string text = "<p style=\"font-family:Calibri; font-size:15pt;\">Hi,<br/><br/><br/><br/>Regards<br/></p>";

HtmlFormatProvider provider = new HtmlFormatProvider();
RadDocument document = new RadDocument();
document = provider.Import(text);

radRichTextBox1.Document = document;

Click on an empty line and you will see that the font is different.

RadRichTextBox large txt documents (20000 rows)are loaded very slowly.

The HtmlFormatProvider does not import correctly html content of div tags and css styles.

Import the following code:
<ol>
  <li>Coffee</li>
  <li></li>
  <li>Milk</li>
</ol

Workaround:

public class MyInputBehavior : InputBehavior
{
    public MyInputBehavior(DocumentView view)
        : base(view)
    {
  
    }
  
    public override bool ProcessKeyPress(System.Windows.Forms.KeyPressEventArgs e)
    {
        // TO DO: You code here
        e.KeyChar = char.ToUpper(e.KeyChar);
        return true;
        // By commenting the base call you are supresing the default logic
        //return base.ProcessKeyPress(e);
    }
}

Then you should replace the default input behavior by using the following code snippet:
this.richTextBox.DocumentView.InputBehavior = new MyInputBehavior(this.richTextBox.DocumentView);

To reproduce:
1 Please change the font via selection list first.
2 Set text cursor to font input field and select the whole text (if not already done).
3 Press backspace or delete key.
4 An error message appears.

Workaround:
protected override void DropDownListFont_SelectedIndexChanged(object sender, PositionChangedEventArgs e)
{
    var ddl = sender as RadDropDownListElement;
    if (ddl.SelectedItem != null)
    {
        base.DropDownListFont_SelectedIndexChanged(sender, e);
    }
}

If you import a rtf document, it produces a span instances with highlight color property set to ARGB(255,0,0,0).

Workaround:

foreach (Span span in document.EnumerateChildrenOfType<Span>())
{
    if (span.HighlightColor == Color.FromArgb(255, 0, 0, 0))
    {
        span.HighlightColor = Color.Transparent;
    }
}

When importing HTML files if the font from the style contains serif element the font does not get interpreted correctly. For example "font-family: 'Times New Roman','serif';" - this will not work, but this font-family: 'Times New Roman';" will work.