Tab stops with visible tab leader (dot, hyphen, underscore) are not exported to PDF.

Steps to reproduce:
- Start with empty document
- In Paragraph Properties dialog, choose Tabs
- In Tab dialog, enter Tab stop position = 2, Leader = underscore, and press Set. Press OK
- Add a word, press Tab, add another word
- Export the text to PDF

Expected: the words are separated with underscores in the exported PDF.
Actual: the words are separated with blank space in the exported PDF.

Pasting HTML content causes RichTextBox to insert a paragraph break, even if the copied content did not include the end of the paragraph.

Steps to reproduce:
1. Copy the first few words in a paragraph from Internet Explorer
2. Paste into the middle of a sentence in the RichTextBox
Expected: The content is pasted inline
Observed: The content is inserted, but a paragraph break is inserted after the content

When cells with borders are copied from Microsoft Excel and pasted in RadRichTextBox, some of the borders are missing depending on their type - for example double borders, but also some other types.

The parent of an already removed span cannot be found and a NullReferenceException is thrown while performing Undo. Also, multiple asserts are failing in Debug mode. The stack trace is:

UnhandledException: Object reference not set to an instance of an object.
UnhandledException:   at Telerik.Windows.Documents.Layout.LayoutElement.SetParent(LayoutElement newParent)
   at Telerik.Windows.Documents.Layout.LayoutBox.EnsureParent()
   at Telerik.Windows.Documents.Layout.LayoutBox.get_Parent()
   at Telerik.Windows.Documents.Layout.LayoutBox.get_ValidParent()
   at Telerik.Windows.Documents.WordPositionHandler.GetParentHandler()
   at Telerik.Windows.Documents.DocumentPosition.GetCurrentSectionBox()
   at Telerik.Windows.Documents.UI.DocumentPrintLayoutPresenter.GetCurrentPage()
   at Telerik.Windows.Documents.UI.DocumentPrintLayoutPresenter.MeasureOverride(Size availableSize)
   at System.Windows.FrameworkElement.MeasureCore(Size availableSize)

Implement built-in support for the Sogou Pinyin Input Method Editor.

Sogou Pinyin is the most popular IME in China (above 80% of the users are using it).

Currently RadRichTextBox doesn't support Sogou Pinyin IME out of the box, and the users have to manually implement it, as described in the "How to implement your own IME support?" (
https://docs.telerik.com/devtools/wpf/controls/radrichtextbox/ime-support#how-to-implement-your-own-ime-support ) help article and the CustomCaret (https://github.com/telerik/xaml-sdk/tree/master/RichTextBox/CustomCaret ) SDK example. 

In Windows 10 1709 Falls creators update there is an upgrade to Microsoft Edge, with which the copy from edge is changed:

1) no longer it is copied in "Rich Text Format"

2) the "HTML Format" data is formatted differently than before - different line separators and the whole html is placed into a single line (unlike before).

RadRichTextBox: Add import/export in the following formats: .mht .odt .epub .doc

Currently, when a page break is added to the document, the paragraph is not split in two. 
It will be better to split the paragraph and add one additional paragraph in order to achieve a more consistent look of the document when applying a style, adding one of the paragraphs to a list or having different first line/hanging indentation of the paragraphs.

Add "Show Grid Lines" command. The command should visualize all table borders, including the invisible ones.

Improve the performance when multiple paragraphs are selected and deleted.

Implement a Page Setup dialog which allows the users to modify Margins, Layout, Page Size, etc. of the document. 

While clicking to position the caret at the beginning of a paragraph, the caret is jumping to the previous document position and returning back to the desired one. 

Fix available in LIB Version 2017.2.627.

If content with DocumentLists and ListStyles respectively, is copied from Microsoft Word and then pasted in RadRichTextBox, ArgumentNullException is thrown while the lists from the DocumentFragment are fixed (FixListStyles() method). 

The exception is caught and thus, the content from the clipboard is not inserted during the copy/paste operation. In some cases, when the content is pasted again, the content is pasted.

Workaround: Replace the fragment in the clipboard with one that is already "fixed". See the attached MainWindow.cs.txt

The caret (cursor) is drawn over letters. This is unpleasant, especially with small font sizes. The issue is even more noticeable when the zoom factor is bigger than 100%.

Available in LIB Version 2018.1.312.

Implement support for exact table row height option. By using this option the text should be clipped when the table row height is lower than the height needed for the text to render. 
The current implementation supports only the at least option.

Most of the CJK characters are not defined or don't look good in fonts not specifically designed for CJK.

Because of this it would be convenient the font to be automatically changed to MS Mincho in case the user starts writing CJK characters. 

Note that if the current font supports CJK (for example Arial Unicode MS), the font is not changed to MS Mincho.

NullReferenceException is thrown when measuring a document with floating image as the first element on a second page. The same problem can be observed during copy/paste of content, but with slightly different call stack: 

System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.Windows.Documents.Layout.LayoutBox.get_ValidParent()
   at Telerik.Windows.Documents.DocumentPosition.GetCurrentParagraphBox()
   at Telerik.Windows.Controls.RichTextBoxUI.RadRichTextBoxRulerController.GetCurrentParagraphBox()
   at Telerik.Windows.Controls.RichTextBoxUI.RadRichTextBoxRulerController.AssociatedRichTextBox_LayoutUpdated(Object sender, EventArgs e)

Depending on the document structure, an InvalidOperationException with message "Removed LayoutBox should not be split. Such operation will result in invalid document structure." could be also thrown. A sample call stack is:

Telerik.Windows.Documents.Layout.LayoutBox.CreateNewFragment(Telerik.Windows.Documents.Layout.LayoutBox currentLineStartNode) 
Telerik.Windows.Documents.Layout.TableCellLayoutBox.MeasureOverrideInternal(Telerik.Windows.Documents.Model.SizeF availableSize) 
Telerik.Windows.Documents.Layout.TableCellLayoutBox.Telerik.Windows.Documents.Model.IBlockContainerLayoutBox.CallMeasureOverrideInternal(Telerik.Windows.Documents.Model.SizeF availableSize) 
Telerik.Windows.Documents.Layout.BlockContainerLayoutHelper.CheckAllFloatingBlocksAreIncluded(Telerik.Windows.Documents.Model.SizeF availableSize) 

Fix available in LIB Version 2018.1.312.

Add support for math type equations.

This property allows the user to set the transparency of the image watermark. In the OOXML, the property is written using the 'blacklevel' attribute of the image.