************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.WinForms.Documents.UI.UIProviders.WatermarkUIProvider.Arrange(UILayerUpdateContext uILayerUpdateContext)
   at Telerik.WinForms.Documents.UI.Layers.ProviderUILayerBase.ArrangeChildren()
   at Telerik.WinForms.Documents.UI.DocumentPrintPresenter.ArrnageUILayers()
   at Telerik.WinForms.Documents.UI.DocumentPrintPresenter.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.RadElement.MeasureCore(SizeF availableSize)
   at Telerik.WinControls.RadElement.Measure(SizeF availableSize)
   at Telerik.WinControls.RadElement.MeasureChildren(SizeF availableSize)
   at Telerik.WinControls.RichTextEditor.UI.FrameworkElement.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.RadElement.MeasureCore(SizeF availableSize)
   at Telerik.WinControls.RadElement.Measure(SizeF availableSize)
   at Telerik.WinControls.Layouts.ContextLayoutManager.UpdateLayout()
   at Telerik.WinForms.Documents.UI.DocumentPrintPresenter.Telerik.WinForms.RichTextEditor.IDocumentEditorPresenter.UpdateLayout()
   at Telerik.WinForms.RichTextEditor.RadRichTextBox.<>c__DisplayClass3.<UpdateEditorLayout>b__2()
   at Telerik.WinForms.RichTextEditor.RadRichTextBox.UpdateEditorLayout(Boolean focusCarret, Boolean updateCaretSize, Boolean async)
   at Telerik.WinForms.RichTextEditor.RadRichTextBox.set_ActiveEditorPresenter(IDocumentEditorPresenter value)
   at Telerik.WinForms.RichTextEditor.RadRichTextBox.Telerik.WinControls.UI.IPrintable.BeginPrint(RadPrintDocument sender, PrintEventArgs args)
   at Telerik.WinControls.UI.RadPrintDocument.OnBeginPrint(PrintEventArgs e)
   at System.Drawing.Printing.PrintDocument._OnBeginPrint(PrintEventArgs e)
   at System.Drawing.Printing.PrintController.Print(PrintDocument document)
   at System.Drawing.Printing.PrintDocument.Print()
   at System.Windows.Forms.PrintPreviewControl.ComputePreview()
   at System.Windows.Forms.PrintPreviewControl.CalculatePageInfo()
   at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme)
   at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry tme)
   at System.Windows.Forms.Control.InvokeMarshaledCallbacks()


To reproduce: please refer to the attached gi file demonstrating how to replicate the problem with the Demo application.

Workaround:

        private void radRichTextEditor1_CommandExecuting(object sender, Telerik.WinForms.Documents.RichTextBoxCommands.CommandExecutingEventArgs e)
        {
            if (e.Command  is ChangeIntegratedWatermarkTypeCommand && this.radRichTextEditor1.LayoutMode!= Telerik.WinForms.Documents.Model.DocumentLayoutMode.Paged)
            {
                e.Cancel = true; 
            }
        }

Use attached to reproduce. 

To reproduce: 
- Load a right to left document with Hebrew characters.
- Export it to PDF
- The characters' position is not correct.

To reproduce:
- Drop RadRichTextEditor  to a form.
- Set the theme to FluentDark. 

Workaround:
radRichTextEditor1.ChangeTextForeColor(Color.White);

or

public void SetBackColor()
{
    this.radRichTextEditor1.RichTextBoxElement.BackColor = Color.White;
    Theme theme = ThemeRepository.FindTheme("TelerikMetroBlue");

    foreach (var styleGroup in theme.StyleGroups)
    {
        foreach (PropertySettingGroup settingGroup in styleGroup.PropertySettingGroups)
        {
            if (settingGroup.Selector.Value == "Telerik.WinControls.RichTextEditor.UI.Page")
            {
                foreach (PropertySetting property in settingGroup.PropertySettings)
                {
                    if (property.Name == "BackColor")
                    {
                        property.Value = System.Drawing.Color.White;
                    }
                }
            }
            if (settingGroup.Selector.Value == "Telerik.WinControls.RichTextEditor.UI.HeaderFooterContainer")
            {
                foreach (PropertySetting property in settingGroup.PropertySettings)
                {
                    if (property.Name == "OverlayColor")
                    {
                        property.Value = System.Drawing.Color.White;
                    }
                }
            }
        }
    }

}

Provide functionality allowing a document to be thumbnailed. The customers should be able to export a document to an image.

Workaround: Use attached project. 

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

Workaround: 

        private void radRichTextEditor1_CommandExecuting(object sender, Telerik.WinForms.Documents.RichTextBoxCommands.CommandExecutingEventArgs e)
        {
            if (e.Command  is ChangeIntegratedWatermarkTypeCommand && this.radRichTextEditor1.LayoutMode!= Telerik.WinForms.Documents.Model.DocumentLayoutMode.Paged)
            {
                e.Cancel = true; 
            }
        }

The following parts are with hard coded strings and cannot be localized:

 - Insert Caption (InsertCaptionDialog): Combo boxes for label and separator
 - Paragraph Properties (ParagraphPropertiesDialog): Units of spacing and indentation values (pt)
 - Tab Stops Properties (TabStopsPropertiesDialog): The text of the tabStopsToBeClearedTextBloc
 - Cross references: reference types Figure and Table
 - TOC  and TOF: Heading and Figure, Caption labels
 - Document Ruler: Tooltips
 - FormattingColorPicker: The "No Color" string
- ManageStylesDialog shows items "Modify" and "Delete" with hardcoded text.

Workaround:

        public TextEditorRadForm()
        {
            InitializeComponent();
            ((RadForm)this.radRichTextEditor1.RichTextBoxElement.InsertCaptionDialog).Controls["radRichTextEditorLabel"].Text = "";
        }

To reproduce: add a RadRichTextEditor with ribbon UI. Set the RichTextEditorRibbonBar's theme to Fluent at design time. When you run the application you will notice that the theme is not properly applied to the backstage view.

Workaround: ThemeResolutionService.ApplicationThemeName = "Fluent";

Workaround: If possible set the layout mode to FlowNoWrap
this.radRichTextEditor1.Document.LayoutMode = Telerik.WinForms.Documents.Model.DocumentLayoutMode.FlowNoWrap;

Currently unknown/unsupported elements are skipped, which potentially loses text content. Consider adding setting in HtmlImportOptions allowing the phrasing content (text) of these elements to be imported. 

Sample HTML:

<html>
<body>
<test-test>test-test</test-test>
<body/>
</html>


Browsers visualize it as "test-test", while RadRichTextBox doesn't import anything.

MS Word imports such elements as inline elements (just like spans).

When there is a hyperlink enclosed in another annotation (e.g comment, bookmark, read-only range), and the user moves the caret position just before or just after the hyperlink, and starts typing there, the text is inserted with the style of the hyperlink (by default, blue with blue underline). Instead, the text should be inserted without such style.

Applying negative LeftIndent or FirstLineIndent of a paragraph in web layout mode will visualize the paragraph to the left of RadRichTextBox boundaries.

To reproduce: run the project, load the document available in the project's folder and start clicking the words. You will notice that the cursor is shifted on the right. 

Workaround: don't enable the RightToLeft property.

Workaround: 
private void RadRichTextEditor1_CommandExecuting(object sender, Telerik.WinForms.Documents.RichTextBoxCommands.CommandExecutingEventArgs e)
{
    if (e.Command is SaveCommand)
    {
        DocumentPosition initial = this.radRichTextEditor1.Document.CaretPosition;
        DocumentPosition start = new DocumentPosition(initial);
        DocumentPosition end = new DocumentPosition(initial);

        var spans = this.radRichTextEditor1.Document.EnumerateChildrenOfType<Span>();
        foreach (var span in spans)
        {
            if (span.FontStyle != FontStyle.Regular)
            {
                continue;
            }

            start.MoveToInline(span);
            end.MoveToEndOfDocumentElement(span);

            this.radRichTextEditor1.Document.Selection.AddSelectionStart(start);
            this.radRichTextEditor1.Document.Selection.AddSelectionEnd(end);

            this.radRichTextEditor1.RichTextBoxElement.Commands.ChangeFontFamilyCommand.Execute("Calibri");
        }

        this.radRichTextEditor1.Document.CaretPosition.MoveToPosition(initial);
    }
}